diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
new file mode 100644
index 00000000000..7a583c1c91b
--- /dev/null
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -0,0 +1,18 @@
+## Description
+<!--- Describe your changes -->
+
+## Screenshots
+<!--- Screenshots (if appropriate) -->
+
+## Type of change
+<!--- What type of changes does your code introduce? -->
+
+- [ ] Bug fix
+- [ ] New feature
+- [ ] Breaking change (fix or feature that would cause existing functionality to change)
+
+## Checklist:
+<!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
+
+- [ ] I have signed [Wire's contributor agreement](https://github.com/wireapp/wire#contributing-to-the-code).
+- [ ] My Pull Request contains test coverage for my changes.
diff --git a/.gitignore b/.gitignore
index c0f8c75de88..14b8360be0d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,11 +25,6 @@
 aws-keys.json
 Gruntfile.js
 npm-debug.log
-strings-ar.coffee
-strings-fr.coffee
-strings-it.coffee
-strings-pt.coffee
-strings-ru.coffee
 
 # Automatically created files
 /doc
diff --git a/app/font/Wire.ttf b/app/font/Wire.ttf
index 447b8456352..88961bf6827 100755
Binary files a/app/font/Wire.ttf and b/app/font/Wire.ttf differ
diff --git a/app/page/auth.html b/app/page/auth.html
index 233813bf43c..68c0a70a507 100644
--- a/app/page/auth.html
+++ b/app/page/auth.html
@@ -161,7 +161,7 @@
                   <input type="checkbox" id="checkbox-terms-of-use" data-bind="checked: accepted_terms_of_use" tabindex="4">
                   <label class="auth-text" for="checkbox-terms-of-use">
                     <span data-bind="l10n_text: z.string.auth_account_terms_of_use_detail" data-uie-name="do-terms-of-use"></span>
-                    <a class="auth-text-link" target="_blank" tabindex="-1"
+                    <a class="auth-text-link" rel="nofollow noopener noreferrer" target="_blank" tabindex="-1"
                        data-bind="click: clicked_on_terms, l10n_text: z.string.auth_account_terms_of_use"
                        data-uie-name="go-terms-of-use"></a>
                   </label>
@@ -272,7 +272,7 @@
           <div class="auth-headline-sub" data-bind="l10n_text: z.string.auth_history_description"></div>
           <div class="footer">
             <div class="button-group">
-              <a class="button button-outline" target="_blank"
+              <a class="button button-outline" rel="nofollow noopener noreferrer" target="_blank"
                  data-bind="l10n_href: z.string.url_support_history, l10n_text: z.string.warning_learn_more"
                  data-uie-name="do-history-learn-more"></a>
             <span class="button button-white"
diff --git a/app/page/template/_dist/app.htm b/app/page/template/_dist/app.htm
index 55fc4dae4b4..d6bc1323af1 100644
--- a/app/page/template/_dist/app.htm
+++ b/app/page/template/_dist/app.htm
@@ -19,7 +19,6 @@
 <script src="/script/util/CountryCodes.js"></script>
 <script src="/script/util/Invite.js"></script>
 <!-- Storage -->
-<script src="/script/storage/SkipError.js"></script>
 <script src="/script/storage/StorageError.js"></script>
 <script src="/script/storage/StorageKey.js"></script>
 <script src="/script/storage/StorageRepository.js"></script>
@@ -36,6 +35,7 @@
 <script src="/script/event/EventError.js"></script>
 <script src="/script/event/EventRepository.js"></script>
 <script src="/script/event/EventTypeHandling.js"></script>
+<script src="/script/event/NotificationHandlingState.js"></script>
 <script src="/script/event/NotificationService.js"></script>
 <script src="/script/event/WebApp.js"></script>
 <script src="/script/event/WebSocketService.js"></script>
@@ -100,6 +100,7 @@
 <!-- GeoLocation -->
 <script src="/script/location/GeoLocation.js"></script>
 <!-- Conversation -->
+<script src="/script/conversation/ConversationError.js"></script>
 <script src="/script/conversation/ConversationType.js"></script>
 <script src="/script/conversation/ConversationStatus.js"></script>
 <script src="/script/conversation/ConversationUnreadType.js"></script>
@@ -202,7 +203,9 @@
 <script src="/script/components/calling/deviceToggleButton.js"></script>
 <!-- Entities -->
 <script src="/script/message/CallMessageType.js"></script>
+<script src="/script/message/StatusType.js"></script>
 <script src="/script/message/PingMessageType.js"></script>
+<script src="/script/message/ReactionType.js"></script>
 <script src="/script/message/SuperType.js"></script>
 <script src="/script/message/SystemMessageType.js"></script>
 <script src="/script/entity/message/Asset.js"></script>
diff --git a/app/page/template/modals.htm b/app/page/template/modals.htm
index 96ff60c3931..66a17871a4f 100644
--- a/app/page/template/modals.htm
+++ b/app/page/template/modals.htm
@@ -144,7 +144,7 @@
         <div class="modal-title" data-bind="l10n_text: z.string.warning_call_headline"></div>
       </div>
       <div class="modal-text" data-bind="l10n_text: z.string.warning_call_detail"></div>
-      <div class="modal-action button button-medium button-fluid" target="_blank" data-bind="l10n_text: z.string.warning_tell_me_how" data-uie-name="go-faq"></div>
+      <div class="modal-action button button-medium button-fluid" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_text: z.string.warning_tell_me_how" data-uie-name="go-faq"></div>
     </div>
   </div>
 
@@ -221,7 +221,7 @@
           </label>
         </div>
       </div>
-      <div class="modal-action button button-medium button-fluid" target="_blank" data-bind="l10n_text: z.string.modal_logout_button" data-uie-name="go-logout"></div>
+      <div class="modal-action button button-medium button-fluid" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_text: z.string.modal_logout_button" data-uie-name="go-logout"></div>
     </div>
   </div>
 
@@ -264,7 +264,7 @@
       </div>
       <div class="modal-text">
         <span data-bind="l10n_text: z.string.modal_session_reset_message_1"></span>
-        <a data-bind="l10n_href: z.string.url_support_contact_bug, l10n_text: z.string.modal_session_reset_message_link" target="_blank"></a>
+        <a data-bind="l10n_href: z.string.url_support_contact_bug, l10n_text: z.string.modal_session_reset_message_link" rel="nofollow noopener noreferrer" target="_blank"></a>
         <span data-bind="l10n_text: z.string.modal_session_reset_message_2"></span>
       </div>
       <div class="modal-close button button-medium button-fluid" data-bind="l10n_text: z.string.modal_button_ok" data-uie-name="do-close"></div>
@@ -290,7 +290,7 @@
       </div>
       <div class="modal-text">
         <span data-bind="l10n_text: z.string.modal_whitelist_screensharing_message_1"></span>
-        <a data-bind="l10n_href: z.string.url_support_screen_whitelist, l10n_text: z.string.modal_whitelist_screensharing_message_link" target="_blank"></a>
+        <a data-bind="l10n_href: z.string.url_support_screen_whitelist, l10n_text: z.string.modal_whitelist_screensharing_message_link" rel="nofollow noopener noreferrer" target="_blank"></a>
         <span data-bind="l10n_text: z.string.modal_whitelist_screensharing_message_2"></span>
       </div>
       <div class="modal-close button button-medium button-fluid" data-bind="l10n_text: z.string.modal_button_ok" data-uie-name="do-close"></div>
diff --git a/app/page/template/partials/template-message.htm b/app/page/template/partials/template-message.htm
index 4aaedca2fab..058a1fb8512 100644
--- a/app/page/template/partials/template-message.htm
+++ b/app/page/template/partials/template-message.htm
@@ -39,7 +39,7 @@
   <div class="message-body message-location-body">
     <div class="message-location-icon icon-location"></div>
     <div class="message-location-label" data-bind="text: name"></div>
-    <a target="_blank" class="label-xs text-theme" data-bind="attr: {href: link_src}, l10n_text: z.string.conversation_location_link"></a>
+    <a class="label-xs text-theme" data-bind="attr: {href: link_src}, l10n_text: z.string.conversation_location_link" rel="nofollow noopener noreferrer" target="_blank"></a>
   </div>
 </script>
 
@@ -69,6 +69,7 @@
     </div>
   </div>
   <div class="message-body">
+
     <!-- ko foreach: {data: message.assets, as: 'asset'} -->
       <!-- ko if: asset.is_medium_image() -->
         <div class="message-asset-image" data-bind="fit_to_viewport: asset">
@@ -106,14 +107,47 @@
       <!-- /ko -->
 
       <context-menu params="entries: function() {return $parents[1].get_context_menu_entries(message)}, tag: 'message', data: message.id"
-                    class="context-menu icon-more"
+                    class="context-menu icon-more font-size-xs"
                     tabindex="-1"></context-menu>
       <!-- ko ifnot: message.timestamp == '' -->
         <time class="time" data-bind="text: message.display_timestamp_short(), attr: {'data-timestamp': message.timestamp, 'data-uie-uid': message.id}" data-uie-name="item-message-timestamp"></time>
       <!-- /ko -->
+    <!-- /ko -->
 
+    <!-- ko ifnot: message.other_likes().length -->
+      <div class="message-body-like">
+        <span class="message-body-like-icon like-button message-show-on-hover" data-bind="attr: {'data-ui-value': message.is_liked()}, css: {'like-button-liked': message.is_liked()}, style: {opacity: message.is_liked() ? 1 : ''}, click: $parent.click_on_like">
+          <span class="icon-liked"></span>
+          <span class="icon-liked"></span>
+        </span>
+      </div>
     <!-- /ko -->
+
   </div>
+  <!-- ko if: message.other_likes().length -->
+    <div class="message-footer">
+      <div class="message-footer-icon">
+        <span class="like-button" data-bind="attr: {'data-ui-value': message.is_liked()}, css: {'like-button-liked': message.is_liked()}, style: {opacity: message.is_liked() ? 1 : ''}, click: $parent.click_on_like">
+          <span class="icon-liked"></span>
+          <span class="icon-liked"></span>
+        </span>
+      </div>
+      <div class="message-footer-label cursor-pointer" data-bind="click: function() {$data.show_likes(true)}">
+        <span class="font-size-xs text-graphite" data-uie-name="message-liked-names" data-bind="text: like_caption, attr: {'data-uie-value': reactions_user_ids()}" ></span>
+        <!-- ko if: !message.show_likes() && message.other_likes().length > 5 -->
+          <span class="icon-more font-size-xs"></span>
+        <!-- /ko -->
+      </div>
+      <!-- ko if: message.show_likes() -->
+        <div class="message-footer-bottom" data-uie-name="message-liked-avatars">
+          <!-- ko foreach: message.reactions_user_ets() -->
+            <user-avatar class="user-avatar-xs" data-bubble="#participants-bubble" data-placement="vertical" params="user: $data, click: $parents[1].on_message_user_click"></user-avatar>
+          <!-- /ko -->
+          <span class="icon-close button-icon font-size-xs flex-center user-avatar-box-xs" data-bind="click: function() { $data.show_likes(false) }"></span>
+        </div>
+      <!-- /ko -->
+    </div>
+  <!-- /ko -->
 </script>
 
 <script type="text/html" id="device">
@@ -189,7 +223,7 @@
     </div>
   </div>
   <context-menu params="entries: function() {return $parent.get_context_menu_entries($data)}, tag: 'message', data: message.id"
-                class="context-menu icon-more"
+                class="context-menu icon-more font-size-xs"
                 tabindex="-1"></context-menu>
   <!-- ko ifnot: message.timestamp == '' -->
     <time class="time" data-bind="text: message.display_timestamp_short(), attr: {'data-timestamp': message.timestamp}"></time>
@@ -218,7 +252,7 @@
     <div class="message-header-label ellipsis">
       <span data-bind="html: caption"></span>
       <span>&nbsp;</span>
-      <a class="text-theme" data-bind="l10n_text: z.string.conversation_unable_to_decrypt_link, attr: {'href': link}" target="_blank"></a>
+      <a class="text-theme" data-bind="l10n_text: z.string.conversation_unable_to_decrypt_link, attr: {'href': link}" rel="nofollow noopener noreferrer" target="_blank"></a>
       <hr class="message-header-line" />
     </div>
   </div>
diff --git a/app/page/template/partials/template-user-profile.htm b/app/page/template/partials/template-user-profile.htm
index eb1aee716a3..bceabb727a6 100644
--- a/app/page/template/partials/template-user-profile.htm
+++ b/app/page/template/partials/template-user-profile.htm
@@ -37,7 +37,7 @@
           <!-- ko if: devices_found() === true -->
             <div class="user-profile-device-message">
               <div data-bind="text: device_headline"></div>
-              <a data-bind="l10n_text: z.string.people_tabs_devices_why_verify, l10n_href: z.string.url_privacy_why" target="_blank" class="text-theme"></a>
+              <a data-bind="l10n_text: z.string.people_tabs_devices_why_verify, l10n_href: z.string.url_privacy_why" rel="nofollow noopener noreferrer" target="_blank" class="text-theme"></a>
             </div>
             <div data-bind="foreach: user().devices">
               <div class="user-profile-device">
@@ -55,7 +55,7 @@
           <!-- /ko -->
           <!-- ko if: devices_found() === false -->
             <div data-bind="text: no_device_headline"></div>
-            <a data-bind="l10n_text: z.string.people_tabs_devices_learn_more, l10n_href: z.string.url_privacy" target="_blank" class="text-theme"></a>
+            <a data-bind="l10n_text: z.string.people_tabs_devices_learn_more, l10n_href: z.string.url_privacy" rel="nofollow noopener noreferrer" target="_blank" class="text-theme"></a>
           <!-- /ko -->
         </div>
       <!-- /ko -->
@@ -71,7 +71,7 @@
         <span class="user-profile-my-device-button user-profile-top-right-button button-label text-theme" data-bind="click: click_on_my_fingerprint_button, l10n_text: z.string.people_tabs_device_detail_show_my_device"></span>
         <div class="user-profile-device-detail-message">
           <div data-bind="html: detail_message"></div>
-          <a data-bind="l10n_text: z.string.people_tabs_device_detail_how_to, l10n_href: z.string.url_privacy_why" target="_blank" class="text-theme"></a>
+          <a data-bind="l10n_text: z.string.people_tabs_device_detail_how_to, l10n_href: z.string.url_privacy_why" rel="nofollow noopener noreferrer" target="_blank" class="text-theme"></a>
         </div>
         <device-card class="user-profile-device-detail-card" params="device: selected_device()"></device-card>
         <div class="user-profile-device-detail-fingerprint" data-bind="html: z.util.print_devices_id(fingerprint_remote())"></div>
diff --git a/app/page/template/self/self-about.htm b/app/page/template/self/self-about.htm
index 135afd1d659..777fdea6394 100644
--- a/app/page/template/self/self-about.htm
+++ b/app/page/template/self/self-about.htm
@@ -10,11 +10,11 @@
       </svg>
     </header>
     <div>
-      <a target="_blank" data-uie-name="go-wire-dot-com" data-bind="l10n_text: z.string.about_wire, l10n_href: z.string.url_wire"></a>
+      <a rel="nofollow noopener noreferrer" target="_blank" data-uie-name="go-wire-dot-com" data-bind="l10n_text: z.string.about_wire, l10n_href: z.string.url_wire"></a>
     </div>
     <ul>
-      <li><a target="_blank" data-uie-name="go-legal" data-bind="l10n_text: z.string.about_legal, l10n_href: z.string.url_legal"></a></li>
-      <li><a target="_blank" data-uie-name="go-privacy" data-bind="l10n_text: z.string.about_privacy, l10n_href: z.string.url_privacy"></a></li>
+      <li><a rel="nofollow noopener noreferrer" target="_blank" data-uie-name="go-legal" data-bind="l10n_text: z.string.about_legal, l10n_href: z.string.url_legal"></a></li>
+      <li><a rel="nofollow noopener noreferrer" target="_blank" data-uie-name="go-privacy" data-bind="l10n_text: z.string.about_privacy, l10n_href: z.string.url_privacy"></a></li>
     </ul>
     <footer data-bind="l10n_text: z.string.about_copyright + ' {{config.CURRENT_VERSION_DATE}}'"></footer>
   </div>
diff --git a/app/page/template/settings.htm b/app/page/template/settings.htm
index dc5767a2f1e..d7bcca135d3 100644
--- a/app/page/template/settings.htm
+++ b/app/page/template/settings.htm
@@ -99,8 +99,8 @@
             <!-- /ko -->
             <!-- ko if: delete_status() === 'dialog' -->
               <p data-uie-name="delete-confirm-text" data-bind="text: delete_confirm_text"></p>
-              <span class="button button-sm" data-uie-name="do-delete-account" data-bind="click: click_on_delete_send">Send</span>
-              <span class="button-label text-theme delete-cancel-button" data-uie-name="do-delete-cancel" data-bind="click: click_on_delete_cancel">Cancel</span>
+              <span class="button button-sm" data-uie-name="do-delete-account" data-bind="click: click_on_delete_send, l10n_text: z.string.modal_button_send"></span>
+              <span class="button-label text-theme delete-cancel-button" data-uie-name="do-delete-cancel" data-bind="click: click_on_delete_cancel, l10n_text: z.string.modal_button_cancel"></span>
             <!-- /ko -->
             <!-- ko if: delete_status() === 'sent' -->
               <span data-uie-name="delete-sent" data-bind="click: click_on_delete, l10n_text: z.string.preferences_email_sent"></span>
diff --git a/app/page/template/warning.htm b/app/page/template/warning.htm
index 5daa27a9cc5..4ff16ac1797 100644
--- a/app/page/template/warning.htm
+++ b/app/page/template/warning.htm
@@ -13,7 +13,7 @@
         <div class="warning-bar warning-bar-feature bg-theme">
           <div class="warning-bar-message">
             <span data-bind="l10n_text: z.string.warning_permission_denied_camera"></span>&nbsp;
-            <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_support_camera_access_denied, l10n_text: z.string.warning_learn_more"></a>
+            <a class="warning-bar-link" data-bind="l10n_href: z.string.url_support_camera_access_denied, l10n_text: z.string.warning_learn_more" rel="nofollow noopener noreferrer" target="_blank"></a>
           </div>
           <span class="warning-bar-close icon-close button-round button-round-dark" data-bind="click: close_warning"></span>
         </div>
@@ -30,7 +30,7 @@
         <div class="warning-bar warning-bar-feature bg-theme">
           <div class="warning-bar-message">
             <span data-bind="l10n_text: z.string.warning_permission_denied_microphone"></span>&nbsp;
-            <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.warning_permission_denied_microphone, l10n_text: z.string.warning_learn_more"></a>
+            <a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.warning_permission_denied_microphone, l10n_text: z.string.warning_learn_more"></a>
           </div>
           <span class="warning-bar-close icon-close button-round button-round-dark" data-bind="click: close_warning"></span>
         </div>
@@ -47,7 +47,7 @@
         <div class="warning-bar warning-bar-feature bg-theme">
           <div class="warning-bar-message">
             <span data-bind="l10n_text: z.string.warning_permission_denied_screen"></span>&nbsp;
-            <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_support_screen_access_denied, l10n_text: z.string.warning_learn_more"></a>
+            <a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.url_support_screen_access_denied, l10n_text: z.string.warning_learn_more"></a>
           </div>
           <span class="warning-bar-close icon-close button-round button-round-dark" data-bind="click: close_warning"></span>
         </div>
@@ -57,7 +57,7 @@
       <div class="warning-bar warning-bar-feature bg-theme">
         <div class="warning-bar-message">
           <span data-bind="l10n_text: z.string.warning_not_found_camera"></span>&nbsp;
-          <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_support_mic_not_found, l10n_text: z.string.warning_learn_more"></a>
+          <a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.url_support_mic_not_found, l10n_text: z.string.warning_learn_more"></a>
         </div>
         <span class="warning-bar-close icon-close button-round button-round-dark" data-bind="click: close_warning"></span>
       </div>
@@ -67,7 +67,7 @@
         <div class="warning-bar warning-bar-feature bg-theme">
           <div class="warning-bar-message">
             <span data-bind="l10n_text: z.string.warning_not_found_microphone"></span>&nbsp;
-            <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_support_mic_not_found, l10n_text: z.string.warning_learn_more"></a>
+            <a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.url_support_mic_not_found, l10n_text: z.string.warning_learn_more"></a>
           </div>
           <span class="warning-bar-close icon-close button-round button-round-dark" data-bind="click: close_warning"></span>
         </div>
@@ -86,13 +86,13 @@
       <!-- ko if: top_warning() === z.ViewModel.WarningType.UNSUPPORTED_INCOMING_CALL -->
       <div class="warning-bar warning-bar-feature bg-theme">
         <!-- ko ifnot: z.util.Environment.browser.chrome -->
-          <div class="warning-bar-message"><span data-bind="l10n_text: {'id': z.string.warning_call_unsupported_incoming, replace: {'placeholder': '%s.first_name', 'content': z.util.escape_html(first_name())}}"></span>&nbsp;<a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_support_calling, l10n_text: z.string.warning_learn_more"></a></div>
+          <div class="warning-bar-message"><span data-bind="l10n_text: {'id': z.string.warning_call_unsupported_incoming, replace: {'placeholder': '%s.first_name', 'content': z.util.escape_html(first_name())}}"></span>&nbsp;<a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.url_support_calling, l10n_text: z.string.warning_learn_more"></a></div>
         <!-- /ko -->
         <!-- ko if: z.util.Environment.browser.chrome -->
           <!-- ko if: z.util.Environment.electron -->
             <div class="warning-bar-message">
               <span data-bind="l10n_text: z.string.warning_call_issues"></span>&nbsp;
-              <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_wire_for_web, l10n_text: z.string.wire_for_web"></a>
+              <a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.url_wire_for_web, l10n_text: z.string.wire_for_web"></a>
             </div>
           <!-- /ko -->
           <!-- ko ifnot: z.util.Environment.electron -->
@@ -108,14 +108,14 @@
           <!-- ko ifnot: z.util.Environment.browser.chrome -->
             <div class="warning-bar-message">
               <span data-bind="l10n_text: z.string.warning_call_unsupported_outgoing"></span>&nbsp;
-              <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_support_calling, l10n_text: z.string.warning_learn_more"></a>
+              <a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.url_support_calling, l10n_text: z.string.warning_learn_more"></a>
             </div>
           <!-- /ko -->
           <!-- ko if: z.util.Environment.browser.chrome -->
             <!-- ko if: z.util.Environment.electron -->
               <div class="warning-bar-message">
                 <span data-bind="l10n_text: z.string.warning_call_issues"></span>&nbsp;
-                <a class="warning-bar-link" target="_blank" data-bind="l10n_href: z.string.url_wire_for_web, l10n_text: z.string.wire_for_web"></a>
+                <a class="warning-bar-link" rel="nofollow noopener noreferrer" target="_blank" data-bind="l10n_href: z.string.url_wire_for_web, l10n_text: z.string.wire_for_web"></a>
               </div>
             <!-- /ko -->
             <!-- ko ifnot: z.util.Environment.electron -->
diff --git a/app/script/announce/AnnounceRepository.coffee b/app/script/announce/AnnounceRepository.coffee
index 20b8d831dc5..687b3afc4b7 100644
--- a/app/script/announce/AnnounceRepository.coffee
+++ b/app/script/announce/AnnounceRepository.coffee
@@ -63,13 +63,13 @@ class z.announce.AnnounceRepository
             requireInteraction: true
 
           amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.ANNOUNCE.SENT, campaign: announce.campaign
-          @logger.log @logger.levels.INFO, "Announcement Shown '#{announce.title}'"
+          @logger.log @logger.levels.INFO, "Announcement '#{announce.title}' shown"
 
-          notification.onclick = (event) =>
+          notification.onclick = =>
             amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.ANNOUNCE.CLICKED, campaign: announce.campaign
-            @logger.log @logger.levels.INFO, "Announcement Clicked '#{announce.title}'"
+            @logger.log @logger.levels.INFO, "Announcement '#{announce.title}' clicked"
             if announce.link
-              window.open announce.link, '_blank'
+              z.util.safe_window_open announce.link
             if announce.refresh
               window.location.reload true
             notification.close()
diff --git a/app/script/assets/AssetCrypto.coffee b/app/script/assets/AssetCrypto.coffee
index 3952aa39be9..2e752338d78 100644
--- a/app/script/assets/AssetCrypto.coffee
+++ b/app/script/assets/AssetCrypto.coffee
@@ -35,26 +35,23 @@ z.assets.AssetCrypto =
 
     window.crypto.getRandomValues iv
 
-    return new Promise (resolve, reject) ->
-      window.crypto.subtle.generateKey {name: 'AES-CBC', length: 256}, true, ['encrypt']
-      .then (ckey) ->
-        key = ckey
+    return window.crypto.subtle.generateKey {name: 'AES-CBC', length: 256}, true, ['encrypt']
+    .then (ckey) ->
+      key = ckey
 
-        window.crypto.subtle.encrypt {name: 'AES-CBC', iv: iv.buffer}, key, plaintext
-      .then (ciphertext) ->
-        iv_ciphertext = new Uint8Array(ciphertext.byteLength + iv.byteLength)
-        iv_ciphertext.set iv, 0
-        iv_ciphertext.set new Uint8Array(ciphertext), iv.byteLength
+      return window.crypto.subtle.encrypt {name: 'AES-CBC', iv: iv.buffer}, key, plaintext
+    .then (ciphertext) ->
+      iv_ciphertext = new Uint8Array(ciphertext.byteLength + iv.byteLength)
+      iv_ciphertext.set iv, 0
+      iv_ciphertext.set new Uint8Array(ciphertext), iv.byteLength
 
-        window.crypto.subtle.digest 'SHA-256', iv_ciphertext
-      .then (digest) ->
-        computed_sha256 = digest
+      return window.crypto.subtle.digest 'SHA-256', iv_ciphertext
+    .then (digest) ->
+      computed_sha256 = digest
 
-        window.crypto.subtle.exportKey 'raw', key
-      .then (key_bytes) ->
-        resolve [key_bytes, computed_sha256, iv_ciphertext.buffer]
-      .catch (error) ->
-        reject error
+      return window.crypto.subtle.exportKey 'raw', key
+    .then (key_bytes) ->
+      return [key_bytes, computed_sha256, iv_ciphertext.buffer]
 
   ###
   @param key_bytes [ArrayBuffer] AES key used for encryption
@@ -64,21 +61,16 @@ z.assets.AssetCrypto =
   @param [ArrayBuffer]
   ###
   decrypt_aes_asset: (ciphertext, key_bytes, reference_sha256) ->
-    return new Promise (resolve, reject) ->
-      window.crypto.subtle.digest 'SHA-256', ciphertext
-      .then (computed_sha256) ->
-        a = new Uint32Array reference_sha256
-        b = new Uint32Array computed_sha256
+    return window.crypto.subtle.digest 'SHA-256', ciphertext
+    .then (computed_sha256) ->
+      a = new Uint32Array reference_sha256
+      b = new Uint32Array computed_sha256
 
-        if not a.every((x, i) -> x is b[i])
-          throw new Error 'Encrypted asset does not match its SHA-256 hash'
+      if not a.every((x, i) -> x is b[i])
+        throw new Error 'Encrypted asset does not match its SHA-256 hash'
 
-        window.crypto.subtle.importKey 'raw', key_bytes, 'AES-CBC', false, ['decrypt']
-      .then (key) ->
-        iv = ciphertext.slice 0, 16
-        img_ciphertext = ciphertext.slice 16
-        window.crypto.subtle.decrypt {name: 'AES-CBC', iv: iv}, key, img_ciphertext
-      .then (img_plaintext) ->
-        resolve img_plaintext
-      .catch (error) ->
-        reject error
+      return window.crypto.subtle.importKey 'raw', key_bytes, 'AES-CBC', false, ['decrypt']
+    .then (key) ->
+      iv = ciphertext.slice 0, 16
+      img_ciphertext = ciphertext.slice 16
+      return window.crypto.subtle.decrypt {name: 'AES-CBC', iv: iv}, key, img_ciphertext
diff --git a/app/script/assets/AssetService.coffee b/app/script/assets/AssetService.coffee
index f81436f9fd5..d9fa58319ef 100644
--- a/app/script/assets/AssetService.coffee
+++ b/app/script/assets/AssetService.coffee
@@ -314,16 +314,17 @@ class z.assets.AssetService
   @deprecated
   @param conversation_id [String] ID of the self conversation
   @param json_payload [Object] First part of the multipart message
-  @param body_payload [Object] Image to be used as new profile picture
+  @param image_data [Uint8Array|ArrayBuffer] encrypted image data
   @param force_sending [Boolean] Force sending
   @param upload_id [String] Identifies the upload request
   ###
-  post_asset_v2: (conversation_id, json_payload, body_payload, force_sending, upload_id) ->
+  post_asset_v2: (conversation_id, json_payload, image_data, force_sending, upload_id) ->
     return new Promise (resolve, reject) =>
       url = @client.create_url "/conversations/#{conversation_id}/otr/assets"
       url = "#{url}?ignore_missing=true" if force_sending
 
-      data = @_create_asset_multipart_body body_payload, json_payload
+      image_data = new Uint8Array image_data
+      data = @_create_asset_multipart_body image_data, json_payload
       pending_uploads = @pending_uploads
 
       xhr = new XMLHttpRequest()
@@ -387,17 +388,15 @@ class z.assets.AssetService
       delete @pending_uploads[upload_id]
 
   ###
-  Post an OTR asset to a conversation.
-
-  @param file [File, Blob] Image
-  @param image [Object] Image to be used as new profile picture
+  Create image proto message.
+  @param image [File, Blob]
   ###
-  create_asset_proto: (file) ->
+  create_image_proto: (image) ->
     original_image = null
     compressed_image = null
     image_bytes = null
 
-    @compress_image file
+    @compress_image image
     .then (data) ->
       [original_image, compressed_image] = data
       return z.util.base64_to_array compressed_image.src
@@ -411,8 +410,21 @@ class z.assets.AssetService
       image_asset.set_height compressed_image.height
       image_asset.set_original_width original_image.width
       image_asset.set_original_height original_image.height
-      image_asset.set_mime_type file.type
+      image_asset.set_mime_type image.type
       image_asset.set_size image_bytes.length
       image_asset.set_otr_key key_bytes
       image_asset.set_sha256 sha256
       return [image_asset, new Uint8Array ciphertext]
+
+  ###
+  Create asset proto message.
+  @param asset [File, Blob]
+  ###
+  create_asset_proto: (asset) ->
+    z.util.load_file_buffer asset
+    .then (file_bytes) ->
+      return z.assets.AssetCrypto.encrypt_aes_asset file_bytes
+    .then ([key_bytes, sha256, ciphertext]) ->
+      asset = new z.proto.Asset()
+      asset.set 'uploaded', new z.proto.Asset.RemoteData key_bytes, sha256
+      return [asset, ciphertext]
diff --git a/app/script/audio/AudioError.coffee b/app/script/audio/AudioError.coffee
index f5ead144e9f..0a1570e16ea 100644
--- a/app/script/audio/AudioError.coffee
+++ b/app/script/audio/AudioError.coffee
@@ -20,11 +20,22 @@ window.z ?= {}
 z.audio ?= {}
 
 class z.audio.AudioError
-  constructor: (message, type) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message
-    @type = type
     @stack = (new Error()).stack
+    @type = type or z.audio.AudioError::TYPE.UNKNOWN
+
+    @message = switch @type
+      when z.audio.AudioError::TYPE.ALREADY_PLAYING
+        'Sound is already playing'
+      when z.audio.AudioError::TYPE.FAILED_TO_PLAY
+        'Failed to play sound'
+      when z.audio.AudioError::TYPE.IGNORED_SOUND
+        'Ignored request to play sound'
+      when z.audio.AudioError::TYPE.NOT_FOUND
+        'AudioElement or ID not found'
+      else
+        'Unknown AudioError'
 
   @:: = new Error()
   @::constructor = @
@@ -33,4 +44,5 @@ class z.audio.AudioError
     FAILED_TO_PLAY: 'z.audio.AudioError::TYPE.FAILED_TO_PLAY'
     IGNORED_SOUND: 'z.audio.AudioError::TYPE.IGNORED_SOUND'
     NOT_FOUND: 'z.audio.AudioError::TYPE.NOT_FOUND'
+    UNKNOWN: 'z.audio.AudioError::TYPE.UNKNOWN'
   }
diff --git a/app/script/audio/AudioRepository.coffee b/app/script/audio/AudioRepository.coffee
index effe6bab8e8..591f31e4e19 100644
--- a/app/script/audio/AudioRepository.coffee
+++ b/app/script/audio/AudioRepository.coffee
@@ -90,10 +90,13 @@ class z.audio.AudioRepository
       @logger.log @logger.levels.INFO, "Playing sound '#{audio_id}' (loop: '#{play_in_loop}')", audio_element
     .catch (error) =>
       switch error.type
-        when z.audio.AudioError::TYPE.FAILED_TO_PLAY
-          @logger.log @logger.levels.ERROR, "Failed playing sound '#{audio_id}': #{error.message}"
         when z.audio.AudioError::TYPE.NOT_FOUND
           @logger.log @logger.levels.ERROR, "Could not find sound '#{audio_id}'"
+        when z.audio.AudioError::TYPE.ALREADY_PLAYING
+          @logger.log @logger.levels.WARN, "Skipped already playing sound '#{audio_id}'"
+        else
+          @logger.log @logger.levels.ERROR, "Failed playing sound '#{audio_id}': #{error.message}"
+          throw error
 
   ###
   Stop playback of a sound.
@@ -108,6 +111,7 @@ class z.audio.AudioRepository
       delete @currently_looping[audio_id] if @currently_looping[audio_id]
     .catch (error) =>
       @logger.log @logger.levels.ERROR, "Failed stopping sound '#{audio_id}': #{error.message}", audio_element
+      throw error
 
   ###
   Check if sound should be played with current setting.
@@ -118,9 +122,9 @@ class z.audio.AudioRepository
   _check_sound_setting: (audio_id) ->
     return new Promise (resolve, reject) =>
       if @sound_setting() is z.audio.AudioSetting.NONE and audio_id not in z.audio.AudioPlayingType.NONE
-        reject new z.audio.AudioError 'Ignored request to play sound: z.audio.AudioPlayingType.NONE', z.audio.AudioError::TYPE.IGNORED_SOUND
+        reject new z.audio.AudioError z.audio.AudioError::TYPE.IGNORED_SOUND
       else if @sound_setting() is z.audio.AudioSetting.SOME and audio_id not in z.audio.AudioPlayingType.SOME
-        reject new z.audio.AudioError 'Ignored request to play sound: z.audio.AudioPlayingType.SOME', z.audio.AudioError::TYPE.IGNORED_SOUND
+        reject new z.audio.AudioError z.audio.AudioError::TYPE.IGNORED_SOUND
       else
         resolve()
 
@@ -146,7 +150,7 @@ class z.audio.AudioRepository
       if @audio_elements[audio_id]
         resolve @audio_elements[audio_id]
       else
-        reject new z.audio.AudioError 'Audio not found', z.audio.AudioError::TYPE.NOT_FOUND
+        reject new z.audio.AudioError z.audio.AudioError::TYPE.NOT_FOUND
 
   ###
   Initialize all sounds.
@@ -166,7 +170,7 @@ class z.audio.AudioRepository
   ###
   _play: (audio_id, audio_element, play_in_loop = false) ->
     if not audio_id or not audio_element
-      return Promise.reject new z.audio.AudioError 'Missing AudioElement or ID', z.audio.AudioError::TYPE.NOT_FOUND
+      return Promise.reject new z.audio.AudioError z.audio.AudioError::TYPE.NOT_FOUND
 
     return new Promise (resolve, reject) =>
       if audio_element.paused
@@ -179,12 +183,12 @@ class z.audio.AudioRepository
           resolve audio_element
 
         if play_promise
-          play_promise.then(_play_success).catch (error) ->
-            reject new z.audio.AudioError error.message, z.audio.AudioError::TYPE.FAILED_TO_PLAY
+          play_promise.then(_play_success).catch ->
+            reject new z.audio.AudioError z.audio.AudioError::TYPE.FAILED_TO_PLAY
         else
           _play_success()
       else
-        reject new z.audio.AudioError 'Sound is already playing', z.audio.AudioError::TYPE.ALREADY_PLAYING
+        reject new z.audio.AudioError z.audio.AudioError::TYPE.ALREADY_PLAYING
 
   ###
   Preload all sounds for immediate playback.
diff --git a/app/script/auth/AccessTokenError.coffee b/app/script/auth/AccessTokenError.coffee
index 72c5332af6c..b0bf7fa1143 100644
--- a/app/script/auth/AccessTokenError.coffee
+++ b/app/script/auth/AccessTokenError.coffee
@@ -20,11 +20,20 @@ window.z ?= {}
 z.auth ?= {}
 
 class z.auth.AccessTokenError
-  constructor: (message, type) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message
-    @type = type
     @stack = (new Error()).stack
+    @type = type or z.auth.AccessTokenError::UNKNOWN
+
+    @message = switch @type
+      when z.auth.AccessTokenError::TYPE.NOT_FOUND_IN_CACHE
+        'No cached access token found in Local Storage'
+      when z.auth.AccessTokenError::TYPE.REFRESH_IN_PROGRESS
+        'Access Token request already in progress'
+      when z.auth.AccessTokenError::TYPE.REQUEST_FAILED
+        'Request to POST for access token failed'
+      when z.auth.AccessTokenError::TYPE.REQUEST_FORBIDDEN
+        'Request to POST for access token forbidden'
 
   @:: = new Error()
   @::constructor = @
diff --git a/app/script/auth/AuthRepository.coffee b/app/script/auth/AuthRepository.coffee
index 12196d8d6eb..7ff5c4a9f34 100644
--- a/app/script/auth/AuthRepository.coffee
+++ b/app/script/auth/AuthRepository.coffee
@@ -146,7 +146,7 @@ class z.auth.AuthRepository
       else if error.type isnt z.auth.AccessTokenError::TYPE.REFRESH_IN_PROGRESS
         @logger.log @logger.levels.ERROR, "Refreshing access token failed: '#{error.type}'", error
         # @todo What do we do in this case?
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
 
   # Get the cached access token from the Amplify store.
   get_cached_access_token: ->
@@ -160,8 +160,7 @@ class z.auth.AuthRepository
         @_schedule_token_refresh z.storage.get_value z.storage.StorageKey.AUTH.ACCESS_TOKEN.EXPIRATION
         resolve()
       else
-        error_message = 'No cached access token found in Local Storage'
-        reject new z.auth.AccessTokenError error_message, z.auth.AccessTokenError::TYPE.NOT_FOUND_IN_CACHE
+        reject new z.auth.AccessTokenError z.auth.AccessTokenError::TYPE.NOT_FOUND_IN_CACHE
 
   ###
   Initially get access-token provided a valid cookie.
@@ -170,9 +169,9 @@ class z.auth.AuthRepository
   get_access_token: =>
     return new Promise (resolve, reject) =>
       if @auth_service.client.is_requesting_access_token()
-        error_message = 'Access Token request already in progress'
-        @logger.log @logger.levels.WARN, error_message
-        reject new z.auth.AccessTokenError error_message, z.auth.AccessTokenError::TYPE.REFRESH_IN_PROGRESS
+        error = new z.auth.AccessTokenError z.auth.AccessTokenError::TYPE.REFRESH_IN_PROGRESS
+        @logger.log @logger.levels.WARN, error.message
+        reject error
       else
         @auth_service.post_access()
         .then (access_token) =>
diff --git a/app/script/auth/AuthService.coffee b/app/script/auth/AuthService.coffee
index 177646b5b32..3e1a14e4582 100644
--- a/app/script/auth/AuthService.coffee
+++ b/app/script/auth/AuthService.coffee
@@ -125,11 +125,9 @@ class z.auth.AuthService
             if jqXHR.responseJSON or jqXHR.responseText?.startsWith '{'
               error = jqXHR.responseJSON or JSON.parse jqXHR.responseText
               if error.code is z.service.BackendClientError::STATUS_CODE.FORBIDDEN
-                error_message = "#{error_description} (#{error.label} - #{error.message})"
-                error = new z.auth.AccessTokenError error_message, z.auth.AccessTokenError::TYPE.REQUEST_FORBIDDEN
+                error = new z.auth.AccessTokenError z.auth.AccessTokenError::TYPE.REQUEST_FORBIDDEN
             else
-              error_message = 'Access token refresh failed'
-              error = new z.auth.AccessTokenError error_message, z.auth.AccessTokenError::TYPE.REQUEST_FAILED
+              error = new z.auth.AccessTokenError z.auth.AccessTokenError::TYPE.REQUEST_FAILED
               Raygun.send error
 
             @save_access_token_in_client()
diff --git a/app/script/calling/CallCenter.coffee b/app/script/calling/CallCenter.coffee
index 2c3a91b8268..43b15051de5 100644
--- a/app/script/calling/CallCenter.coffee
+++ b/app/script/calling/CallCenter.coffee
@@ -100,14 +100,16 @@ class z.calling.CallCenter
   @param event [Object] Event payload
   ###
   on_event: (event) =>
-    return if @state_handler.is_handling_notifications() or event.type not in SUPPORTED_EVENTS
+    return if event.type not in SUPPORTED_EVENTS
 
-    @logger.log @logger.levels.INFO,
-      "»» Event: '#{event.type}'", {event_object: event, event_json: JSON.stringify event}
-    if z.calling.CallCenter.supports_calling()
-      @_on_event_in_supported_browsers event
+    if @state_handler.block_event_handling
+      @logger.log @logger.levels.INFO, "Skipping '#{event.type}' event", {event_object: event, event_json: JSON.stringify event}
     else
-      @_on_event_in_unsupported_browsers event
+      @logger.log @logger.levels.INFO, "Handling '#{event.type}' event", {event_object: event, event_json: JSON.stringify event}
+      if z.calling.CallCenter.supports_calling()
+        @_on_event_in_supported_browsers event
+      else
+        @_on_event_in_unsupported_browsers event
 
   ###
   Backend calling event handling for browsers supporting calling.
@@ -135,12 +137,12 @@ class z.calling.CallCenter
     switch event.type
       when z.event.Backend.CONVERSATION.VOICE_CHANNEL_ACTIVATE
         @user_repository.get_user_by_id @get_creator_id(event), (creator_et) ->
-          amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.UNSUPPORTED_INCOMING_CALL, {
+          amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.UNSUPPORTED_INCOMING_CALL, {
             first_name: creator_et.name()
             call_id: event.conversation
           }
       when z.event.Backend.CONVERSATION.VOICE_CHANNEL_DEACTIVATE
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.UNSUPPORTED_INCOMING_CALL
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.UNSUPPORTED_INCOMING_CALL
 
 
   ###############################################################################
diff --git a/app/script/calling/CallError.coffee b/app/script/calling/CallError.coffee
index 602f728f8bb..8504646cc88 100644
--- a/app/script/calling/CallError.coffee
+++ b/app/script/calling/CallError.coffee
@@ -20,27 +20,59 @@ window.z ?= {}
 z.calling ?= {}
 
 class z.calling.CallError
-  constructor: (message) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message or z.calling.CallError::TYPE.UNKNOWN
     @stack = (new Error()).stack
+    @type = type or z.calling.CallError::TYPE.UNKNOWN
+
+    @message = switch @type
+      when z.calling.CallError::TYPE.CALL_NOT_FOUND
+        'No call for conversation ID found'
+      when z.calling.CallError::TYPE.CONVERSATION_EMPTY
+        'No users in conversation'
+      when z.calling.CallError::TYPE.CONVERSATION_TOO_BIG
+        'Too many participants in conversation'
+      when z.calling.CallError::TYPE.FLOW_NOT_FOUND
+        'Flow not found'
+      when z.calling.CallError::TYPE.NO_AUDIO_STREAM_FOUND
+        'No audio stream found to toggle mute state'
+      when z.calling.CallError::TYPE.NO_CAMERA_FOUND
+        'No camera found'
+      when z.calling.CallError::TYPE.NO_CONVERSATION_ID
+        'No conversation ID given'
+      when z.calling.CallError::TYPE.NO_DEVICES_FOUND
+        'No MediaDevices found'
+      when z.calling.CallError::TYPE.NO_MICROPHONE_FOUND
+        'No microphone found'
+      when z.calling.CallError::TYPE.NO_REPLACEABLE_TRACK
+        'No replaceable MediaStreamTrack found'
+      when z.calling.CallError::TYPE.NOT_SUPPORTED
+        'Not supported'
+      when z.calling.CallError::TYPE.RTP_SENDER_NOT_SUPPORTED
+        'PeerConnection does not support getSenders()'
+      when z.calling.CallError::TYPE.SCREEN_NOT_SUPPORTED
+        'Screen sharing is not yet supported by this browser'
+      when z.calling.CallError::TYPE.VOICE_CHANNEL_FULL
+        'Too many participants in call'
+      else
+        'Unknown CallError'
 
   @:: = new Error()
   @::constructor = @
   @::TYPE = {
-    CALL_NOT_FOUND: 'No call for conversation ID found'
-    CONVERSATION_EMPTY: 'No users in conversation'
-    CONVERSATION_TOO_BIG: 'Too many participants in conversation'
-    FLOW_NOT_FOUND: 'Flow not found'
-    NO_AUDIO_STREAM_FOUND: 'No audio stream found to toggle mute state'
-    NO_CAMERA_FOUND: 'No camera found'
-    NO_CONVERSATION_ID: 'No conversation ID given'
-    NO_DEVICES_FOUND: 'No MediaDevices found'
-    NO_MICROPHONE_FOUND: 'No microphone found'
-    NO_REPLACEABLE_TRACK: 'No replaceable MediaStreamTrack found'
-    NOT_SUPPORTED: 'Not supported'
-    RTP_SENDER_NOT_SUPPORTED: 'PeerConnection does not support getSenders()'
-    SCREEN_NOT_SUPPORTED: 'Screen sharing is not yet supported by this browser'
-    UNKNOWN: 'Unknown CallError'
-    VOICE_CHANNEL_FULL: 'Too many participants in call'
+    CALL_NOT_FOUND: 'z.calling.CallError::TYPE.CALL_NOT_FOUND'
+    CONVERSATION_EMPTY: 'z.calling.CallError::TYPE.CONVERSATION_EMPTY'
+    CONVERSATION_TOO_BIG: 'z.calling.CallError::TYPE.CONVERSATION_TOO_BIG'
+    FLOW_NOT_FOUND: 'z.calling.CallError::TYPE.FLOW_NOT_FOUND'
+    NO_AUDIO_STREAM_FOUND: 'z.calling.CallError::TYPE.NO_AUDIO_STREAM_FOUND'
+    NO_CAMERA_FOUND: 'z.calling.CallError::TYPE.NO_CAMERA_FOUND'
+    NO_CONVERSATION_ID: 'z.calling.CallError::TYPE.NO_CONVERSATION_ID'
+    NO_DEVICES_FOUND: 'z.calling.CallError::TYPE.NO_DEVICES_FOUND'
+    NO_MICROPHONE_FOUND: 'z.calling.CallError::TYPE.NO_MICROPHONE_FOUND'
+    NO_REPLACEABLE_TRACK: 'z.calling.CallError::TYPE.NO_REPLACEABLE_TRACK'
+    NOT_SUPPORTED: 'z.calling.CallError::TYPE.NOT_SUPPORTED'
+    RTP_SENDER_NOT_SUPPORTED: 'z.calling.CallError::TYPE.RTP_SENDER_NOT_SUPPORTED'
+    SCREEN_NOT_SUPPORTED: 'z.calling.CallError::TYPE.SCREEN_NOT_SUPPORTED'
+    UNKNOWN: 'z.calling.CallError::TYPE.UNKNOWN'
+    VOICE_CHANNEL_FULL: 'z.calling.CallError::TYPE.VOICE_CHANNEL_FULL'
   }
diff --git a/app/script/calling/entities/Call.coffee b/app/script/calling/entities/Call.coffee
index c6110dc7940..ed570e1e0ae 100644
--- a/app/script/calling/entities/Call.coffee
+++ b/app/script/calling/entities/Call.coffee
@@ -111,11 +111,8 @@ class z.calling.entities.Call
       return @self_user_joined() and not @self_client_joined()
 
     @network_interruption = ko.pureComputed =>
-      if @is_connected()
-        if @is_group()
-          return @interrupted_participants().length > 0 and @interrupted_participants().length is @participants().length
-        else
-          return @interrupted_participants().length > 0
+      if @is_connected() and not @is_group()
+        return @interrupted_participants().length > 0
       return false
 
     @network_interruption.subscribe (is_interrupted) ->
diff --git a/app/script/calling/entities/Flow.coffee b/app/script/calling/entities/Flow.coffee
index d04e5bc4a52..f7889251e73 100644
--- a/app/script/calling/entities/Flow.coffee
+++ b/app/script/calling/entities/Flow.coffee
@@ -170,11 +170,13 @@ class z.calling.entities.Flow
       progress_gathering_states = [z.calling.rtc.ICEGatheringState.GATHERING, z.calling.rtc.ICEGatheringState.COMPLETE]
       in_progress = in_connection_progress and @gathering_state() in progress_gathering_states
 
-      in_offer_state = @local_sdp_type() is z.calling.rtc.SDPType.OFFER
-      in_wrong_state = in_offer_state and @signaling_state() is z.calling.rtc.SignalingState.REMOTE_OFFER
-      is_blocked = @signaling_state() is z.calling.rtc.SignalingState.CLOSED
+      is_answer = @local_sdp_type() is z.calling.rtc.SDPType.ANSWER
+      is_offer = @local_sdp_type() is z.calling.rtc.SDPType.OFFER
+      in_remote_offer_state = @signaling_state() is z.calling.rtc.SignalingState.REMOTE_OFFER
+      in_stable_state = @signaling_state() is z.calling.rtc.SignalingState.STABLE
+      in_proper_state = (is_offer and in_stable_state) or (is_answer and in_remote_offer_state)
 
-      return @local_sdp() and @should_add_local_sdp() and not is_blocked and not in_progress and not in_wrong_state
+      return @local_sdp() and @should_add_local_sdp() and in_proper_state and not in_progress
 
     @can_set_local_sdp.subscribe (can_set) =>
       if can_set
@@ -196,11 +198,13 @@ class z.calling.entities.Flow
     @should_add_remote_sdp = ko.observable false
 
     @can_set_remote_sdp = ko.pureComputed =>
-      is_remote_offer = @remote_sdp_type() is z.calling.rtc.SDPType.OFFER
-      have_local_offer = @signaling_state() is z.calling.rtc.SignalingState.LOCAL_OFFER
-      in_wrong_state = is_remote_offer and have_local_offer
+      is_answer = @remote_sdp_type() is z.calling.rtc.SDPType.ANSWER
+      is_offer = @remote_sdp_type() is z.calling.rtc.SDPType.OFFER
+      in_local_offer_state = @signaling_state() is z.calling.rtc.SignalingState.LOCAL_OFFER
+      in_stable_state = @signaling_state() is z.calling.rtc.SignalingState.STABLE
+      in_proper_state = (is_offer and in_stable_state) or (is_answer and in_local_offer_state)
 
-      return @pc_initialized() and @should_add_remote_sdp() and not in_wrong_state
+      return @pc_initialized() and @should_add_remote_sdp() and in_proper_state
 
     @can_set_remote_sdp.subscribe (can_set) =>
       if can_set
@@ -457,7 +461,6 @@ class z.calling.entities.Flow
     sdp_info = new z.calling.payloads.SDPInfo {conversation_id: @conversation_id, flow_id: @id, sdp: @local_sdp()}
 
     on_success = =>
-      @_clear_send_sdp_timeout()
       @has_sent_local_sdp true
       @logger.log @logger.levels.INFO, "Sending local SDP of type '#{@local_sdp().type}' successful"
       @telemetry.time_step z.telemetry.calling.CallSetupSteps.LOCAL_SDP_SEND
@@ -466,6 +469,7 @@ class z.calling.entities.Flow
       @logger.log @logger.levels.WARN, "Failed to send local SDP of type '#{@local_sdp().type}'"
       @reset_flow() if error.code is z.service.BackendClientError::STATUS_CODE.NOT_FOUND
 
+    @_clear_send_sdp_timeout()
     @logger.log @logger.levels.INFO, "Sending local SDP for flow with '#{@remote_user.name()}'\n#{@local_sdp().sdp}"
     amplify.publish z.event.WebApp.CALL.SIGNALING.SEND_LOCAL_SDP_INFO, sdp_info, on_success, on_failure
 
@@ -775,7 +779,7 @@ class z.calling.entities.Flow
   update_media_stream: (media_stream_info) =>
     @_replace_media_track media_stream_info
     .catch (error) =>
-      if error.message in [z.calling.CallError::TYPE.NO_REPLACEABLE_TRACK, z.calling.CallError::TYPE.RTP_SENDER_NOT_SUPPORTED]
+      if error.type in [z.calling.CallError::TYPE.NO_REPLACEABLE_TRACK, z.calling.CallError::TYPE.RTP_SENDER_NOT_SUPPORTED]
         @logger.log @logger.levels.INFO, "Replacement of MediaStream and renegotiation necessary: #{error.message}", error
         return @_replace_media_stream media_stream_info
       throw error
@@ -857,7 +861,7 @@ class z.calling.entities.Flow
       @logger.log @logger.levels.INFO, "Replaced the '#{media_stream_info.type}' track"
       return media_stream_info
     .catch (error) =>
-      if error.message not in [z.calling.CallError::TYPE.NOT_SUPPORTED, z.calling.CallError::TYPE.RTP_SENDER_NOT_SUPPORTED]
+      if error.type not in [z.calling.CallError::TYPE.NOT_SUPPORTED, z.calling.CallError::TYPE.RTP_SENDER_NOT_SUPPORTED]
         @logger.log @logger.levels.ERROR, "Failed to replace the '#{media_stream_info.type}' track: #{error.name} - #{error.message}", error
       throw error
 
diff --git a/app/script/calling/handler/CallSignalingHandler.coffee b/app/script/calling/handler/CallSignalingHandler.coffee
index f0558e88536..3497c8f944e 100644
--- a/app/script/calling/handler/CallSignalingHandler.coffee
+++ b/app/script/calling/handler/CallSignalingHandler.coffee
@@ -121,7 +121,7 @@ class z.calling.handler.CallSignalingHandler
       else
         throw new z.calling.CallError z.calling.CallError::TYPE.FLOW_NOT_FOUND
     .catch (error) =>
-      if error.message is z.calling.CallError::TYPE.FLOW_NOT_FOUND
+      if error.type is z.calling.CallError::TYPE.FLOW_NOT_FOUND
         if event.state is z.calling.rtc.SDPType.OFFER
           @_cache_remote_sdp event.flow, remote_sdp
           @logger.log @logger.levels.INFO, "Cached remote SDP for unknown flow '#{event.flow}'", remote_sdp
@@ -177,7 +177,7 @@ class z.calling.handler.CallSignalingHandler
         @logger.log @logger.levels.DEBUG, "POSTing for flows in '#{conversation_id}' successful", response
         @_add_flow call_et, flow for flow in response.flows when flow.active is true
     .catch (error) =>
-      if error.message is z.calling.CallError::TYPE.CALL_NOT_FOUND
+      if error.type is z.calling.CallError::TYPE.CALL_NOT_FOUND
         @logger.log @logger.levels.WARN, "POSTing for flows in '#{conversation_id}' successful, call gone", error
       else
         @logger.log @logger.levels.ERROR,
diff --git a/app/script/calling/handler/CallStateHandler.coffee b/app/script/calling/handler/CallStateHandler.coffee
index c268406a6f8..8aa2588e8a5 100644
--- a/app/script/calling/handler/CallStateHandler.coffee
+++ b/app/script/calling/handler/CallStateHandler.coffee
@@ -34,7 +34,7 @@ class z.calling.handler.CallStateHandler
 
     @self_state = @call_center.media_stream_handler.self_stream_state
 
-    @is_handling_notifications = ko.observable true
+    @block_event_handling = true
     @subscribe_to_events()
     return
 
@@ -83,12 +83,12 @@ class z.calling.handler.CallStateHandler
   ###
   Set the notification handling state.
   @note Temporarily ignore call related events when handling notifications from the stream
-  @param handling_notifications [Boolean] Notifications are being handled from the stream
+  @param handling_state [z.event.NotificationHandlingState] State of the notifications stream handling
   ###
-  set_notification_handling_state: (handling_notifications) =>
-    @is_handling_notifications handling_notifications
-    @_update_ongoing_calls() if not @is_handling_notifications()
-    @logger.log @logger.levels.INFO, "Ignoring call events: #{handling_notifications}"
+  set_notification_handling_state: (handling_state) =>
+    @block_event_handling = handling_state isnt z.event.NotificationHandlingState.WEB_SOCKET
+    @_update_ongoing_calls() if not @block_event_handling
+    @logger.log @logger.levels.INFO, "Block handling of call events: #{@block_event_handling}"
 
   ###
   Update state of currently ongoing calls.
@@ -137,7 +137,7 @@ class z.calling.handler.CallStateHandler
       else
         @delete_call call_et.id
     .catch (error) =>
-      if error.message is z.calling.CallError::TYPE.CALL_NOT_FOUND
+      if error.type is z.calling.CallError::TYPE.CALL_NOT_FOUND
         # Call with us joined
         if self_user_joined
           # ...from this device
@@ -247,15 +247,15 @@ class z.calling.handler.CallStateHandler
     @call_center.media_stream_handler.release_media_streams()
     switch error.label
       when z.service.BackendClientError::LABEL.CONVERSATION_TOO_BIG
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CALL_FULL_CONVERSATION,
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CALL_FULL_CONVERSATION,
           data: error.max_members
         throw new z.calling.CallError z.calling.CallError::TYPE.CONVERSATION_TOO_BIG
       when z.service.BackendClientError::LABEL.INVALID_OPERATION
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CALL_EMPTY_CONVERSATION
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CALL_EMPTY_CONVERSATION
         @delete_call conversation_id
         throw new z.calling.CallError z.calling.CallError::TYPE.CONVERSATION_EMPTY
       when z.service.BackendClientError::LABEL.VOICE_CHANNEL_FULL
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CALL_FULL_VOICE_CHANNEL,
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CALL_FULL_VOICE_CHANNEL,
           data: error.max_joined
         throw new z.calling.CallError z.calling.CallError::TYPE.VOICE_CHANNEL_FULL
       # User has been removed from conversation, call should be deleted
@@ -369,7 +369,7 @@ class z.calling.handler.CallStateHandler
       return z.calling.enum.CallState.OUTGOING
     .then (call_state) =>
       if call_state is z.calling.enum.CallState.OUTGOING and not z.calling.CallCenter.supports_calling()
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.UNSUPPORTED_OUTGOING_CALL
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.UNSUPPORTED_OUTGOING_CALL
       else
         @call_center.conversation_repository.get_conversation_by_id conversation_id, (conversation_et) =>
           @_check_concurrent_joined_call conversation_id, call_state
@@ -481,7 +481,7 @@ class z.calling.handler.CallStateHandler
       ongoing_call_id = @_self_participant_on_a_call()
       if ongoing_call_id
         @logger.log @logger.levels.WARN, 'You cannot start a second call while already participating in another one.'
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CALL_START_ANOTHER,
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CALL_START_ANOTHER,
           action: =>
             @leave_call ongoing_call_id
             window.setTimeout resolve, 1000
@@ -518,7 +518,7 @@ class z.calling.handler.CallStateHandler
   _join_call: (conversation_id, is_videod) ->
     @call_center.get_call_by_id conversation_id
     .catch (error) ->
-      throw error if error.message isnt z.calling.CallError::TYPE.CALL_NOT_FOUND
+      throw error if error.type isnt z.calling.CallError::TYPE.CALL_NOT_FOUND
     .then =>
       if @call_center.media_stream_handler.has_media_streams()
         @logger.log @logger.levels.INFO, 'MediaStream has already been initialized', @call_center.media_stream_handler.local_media_streams
diff --git a/app/script/calling/handler/MediaStreamHandler.coffee b/app/script/calling/handler/MediaStreamHandler.coffee
index e58a7551069..2b0ec963db8 100644
--- a/app/script/calling/handler/MediaStreamHandler.coffee
+++ b/app/script/calling/handler/MediaStreamHandler.coffee
@@ -343,11 +343,11 @@ class z.calling.handler.MediaStreamHandler
   _hide_permission_failed_hint: (media_type) ->
     switch media_type
       when z.calling.enum.MediaType.AUDIO
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.DENIED_MICROPHONE
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.DENIED_MICROPHONE
       when z.calling.enum.MediaType.SCREEN
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.DENIED_SCREEN
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.DENIED_SCREEN
       when z.calling.enum.MediaType.VIDEO
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.DENIED_CAMERA
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.DENIED_CAMERA
 
   ###
   Hide the permission request hint banner.
@@ -358,11 +358,11 @@ class z.calling.handler.MediaStreamHandler
     return if z.util.Environment.electron
     switch media_type
       when z.calling.enum.MediaType.AUDIO
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.REQUEST_MICROPHONE
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.REQUEST_MICROPHONE
       when z.calling.enum.MediaType.SCREEN
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.REQUEST_SCREEN
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.REQUEST_SCREEN
       when z.calling.enum.MediaType.VIDEO
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.REQUEST_CAMERA
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.REQUEST_CAMERA
 
   ###
   Initial request for local MediaStream was successful.
@@ -426,7 +426,7 @@ class z.calling.handler.MediaStreamHandler
     if media_type is z.calling.enum.MediaType.SCREEN
       if z.util.Environment.browser.firefox and error.name is z.calling.rtc.MediaStreamError.NOT_ALLOWED_ERROR
         @logger.log @logger.levels.WARN, 'We are not on the white list. Manually add the current domain to media.getusermedia.screensharing.allowed_domains on about:config'
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.WHITELIST_SCREENSHARING
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.WHITELIST_SCREENSHARING
       else
         @logger.log @logger.levels.ERROR, "Failed to enable screen sharing: #{error.message}", error
     else
@@ -441,9 +441,9 @@ class z.calling.handler.MediaStreamHandler
   ###
   _show_device_not_found_hint: (media_type, conversation_id) ->
     if media_type is z.calling.enum.MediaType.AUDIO
-      amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.NOT_FOUND_MICROPHONE
+      amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.NOT_FOUND_MICROPHONE
     else if media_type is z.calling.enum.MediaType.VIDEO
-      amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.NOT_FOUND_CAMERA
+      amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.NOT_FOUND_CAMERA
     amplify.publish z.event.WebApp.CALL.STATE.IGNORE, conversation_id if conversation_id
 
   ###
@@ -454,11 +454,11 @@ class z.calling.handler.MediaStreamHandler
   _show_permission_denied_hint: (media_type) ->
     switch media_type
       when z.calling.enum.MediaType.AUDIO
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.DENIED_MICROPHONE
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.DENIED_MICROPHONE
       when z.calling.enum.MediaType.SCREEN
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.DENIED_SCREEN
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.DENIED_SCREEN
       when z.calling.enum.MediaType.VIDEO
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.DENIED_CAMERA
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.DENIED_CAMERA
 
   ###
   Show permission request hint banner.
@@ -469,11 +469,11 @@ class z.calling.handler.MediaStreamHandler
     return if z.util.Environment.electron
     switch media_type
       when z.calling.enum.MediaType.AUDIO
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.REQUEST_MICROPHONE
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.REQUEST_MICROPHONE
       when z.calling.enum.MediaType.SCREEN
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.REQUEST_SCREEN
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.REQUEST_SCREEN
       when z.calling.enum.MediaType.VIDEO
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.REQUEST_CAMERA
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.REQUEST_CAMERA
 
 
   ###############################################################################
diff --git a/app/script/client/ClientError.coffee b/app/script/client/ClientError.coffee
index 6ace75a396b..b7d36bd28fb 100644
--- a/app/script/client/ClientError.coffee
+++ b/app/script/client/ClientError.coffee
@@ -20,11 +20,32 @@ window.z ?= {}
 z.client ?= {}
 
 class z.client.ClientError
-  constructor: (message, type) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message
-    @type = type
     @stack = (new Error()).stack
+    @type = type or z.client.ClientError::TYPE.UNKNOWN
+
+    @message = switch @type
+      when z.client.ClientError::TYPE.CLIENT_NOT_SET
+        'Local client is not yet set'
+      when z.client.ClientError::TYPE.DATABASE_FAILURE
+        'Client related database transaction failed'
+      when z.client.ClientError::TYPE.MISSING_ON_BACKEND
+        'Local client does not exist on backend'
+      when z.client.ClientError::TYPE.NO_CLIENT_ID
+        'Client ID is not defined'
+      when z.client.ClientError::TYPE.NO_LOCAL_CLIENT
+        'No local client found in database'
+      when z.client.ClientError::TYPE.NO_USER_ID
+        'User ID is not defined'
+      when z.client.ClientError::TYPE.REQUEST_FAILURE
+        'Client related backend request failed'
+      when z.client.ClientError::TYPE.REQUEST_FORBIDDEN
+        'Client related backend request forbidden'
+      when z.client.ClientError::TYPE.TOO_MANY_CLIENTS
+        'User has reached the maximum of allowed clients'
+      else
+        'Unknown ClientError'
 
   @:: = new Error()
   @::constructor = @
@@ -38,4 +59,5 @@ class z.client.ClientError
     REQUEST_FAILURE: 'z.client.ClientError::TYPE.REQUEST_FAILURE'
     REQUEST_FORBIDDEN: 'z.client.ClientError::TYPE.REQUEST_FORBIDDEN'
     TOO_MANY_CLIENTS: 'z.client.ClientError::TYPE.TOO_MANY_CLIENTS'
+    UNKNOWN: 'z.client.ClientError::TYPE.UNKNOWN'
   }
diff --git a/app/script/client/ClientRepository.coffee b/app/script/client/ClientRepository.coffee
index 881b8743044..436db79b176 100644
--- a/app/script/client/ClientRepository.coffee
+++ b/app/script/client/ClientRepository.coffee
@@ -29,8 +29,8 @@ class z.client.ClientRepository
     @clients = ko.observableArray()
     @current_client = ko.observable undefined
 
-    amplify.subscribe z.event.Backend.USER.CLIENT.ADD, @on_client_add
-    amplify.subscribe z.event.Backend.USER.CLIENT.REMOVE, @on_client_remove
+    amplify.subscribe z.event.Backend.USER.CLIENT_ADD, @on_client_add
+    amplify.subscribe z.event.Backend.USER.CLIENT_REMOVE, @on_client_remove
     amplify.subscribe z.event.WebApp.CLIENT.DELETE, @delete_client_and_session
 
     return @
@@ -92,13 +92,12 @@ class z.client.ClientRepository
   ###
   get_current_client_from_db: =>
     @client_service.load_client_from_db @PRIMARY_KEY_CURRENT_CLIENT
-    .catch (error) ->
-      throw new z.client.ClientError error.message, z.client.ClientError::TYPE.DATABASE_FAILURE
+    .catch ->
+      throw new z.client.ClientError z.client.ClientError::TYPE.DATABASE_FAILURE
     .then (client_payload) =>
       if _.isString client_payload
-        error_message = "No current local client connected to '#{@PRIMARY_KEY_CURRENT_CLIENT}' found in database"
-        @logger.log @logger.levels.INFO, error_message
-        throw new z.client.ClientError error_message, z.client.ClientError::TYPE.NO_LOCAL_CLIENT
+        @logger.log @logger.levels.INFO, "No current local client connected to '#{@PRIMARY_KEY_CURRENT_CLIENT}' found in database"
+        throw new z.client.ClientError z.client.ClientError::TYPE.NO_LOCAL_CLIENT
       else
         client_et = @client_mapper.map_client client_payload
         @current_client client_et
@@ -130,8 +129,8 @@ class z.client.ClientRepository
   @return [String] Primary key
   ###
   _construct_primary_key: (user_id, client_id) ->
-    throw new z.client.ClientError 'User ID is not defined', z.client.ClientError::TYPE.NO_USER_ID if not user_id
-    throw new z.client.ClientError 'Client ID is not defined', z.client.ClientError::TYPE.NO_CLIENT_ID if not client_id
+    throw new z.client.ClientError z.client.ClientError::TYPE.NO_USER_ID if not user_id
+    throw new z.client.ClientError z.client.ClientError::TYPE.NO_CLIENT_ID if not client_id
     return "#{user_id}@#{client_id}"
 
   ###
@@ -205,11 +204,10 @@ class z.client.ClientRepository
         @logger.log @logger.levels.WARN, error_message, error
         @cryptography_repository.storage_repository.delete_everything()
         .catch (error) =>
-          error_message = "Deleting database after failed client validation unsuccessful: #{error.message}"
-          @logger.log @logger.levels.ERROR, error_message, error
-          throw new z.client.ClientError error_message, z.client.ClientError::TYPE.DATABASE_FAILURE
+          @logger.log @logger.levels.ERROR, "Deleting database after failed client validation unsuccessful: #{error.message}", error
+          throw new z.client.ClientError z.client.ClientError::TYPE.DATABASE_FAILURE
         .then ->
-          throw new z.client.ClientError error_message, z.client.ClientError::TYPE.MISSING_ON_BACKEND
+          throw new z.client.ClientError z.client.ClientError::TYPE.MISSING_ON_BACKEND
       else if error.type is z.client.ClientError::TYPE.NO_LOCAL_CLIENT
         throw error
       else
@@ -234,11 +232,10 @@ class z.client.ClientRepository
         return @client_service.post_clients @_create_registration_payload client_type, password, keys
       .catch (error) =>
         if error.label is z.service.BackendClientError::LABEL.TOO_MANY_CLIENTS
-          throw new z.client.ClientError error.message, z.client.ClientError::TYPE.TOO_MANY_CLIENTS
+          throw new z.client.ClientError z.client.ClientError::TYPE.TOO_MANY_CLIENTS
         else
-          error_message = "Client registration request failed: #{error.message}"
-          @logger.log @logger.levels.ERROR, error_message, error
-          throw new z.client.ClientError error_message, z.client.ClientError::TYPE.REQUEST_FAILURE
+          @logger.log @logger.levels.ERROR, "Client registration request failed: #{error.message}", error
+          throw new z.client.ClientError z.client.ClientError::TYPE.REQUEST_FAILURE
       .then (response) =>
         @logger.log @logger.levels.INFO,
           "Registered '#{response.type}' client '#{response.id}' with cookie label '#{response.cookie}'", response
@@ -249,9 +246,8 @@ class z.client.ClientRepository
         if error.type in [z.client.ClientError::TYPE.REQUEST_FAILURE, z.client.ClientError::TYPE.TOO_MANY_CLIENTS]
           throw error
         else
-          error_message = "Failed to save client: #{error.message}"
-          @logger.log @logger.levels.ERROR, error_message, error
-          throw new z.client.ClientError error_message, z.client.ClientError::TYPE.DATABASE_FAILURE
+          @logger.log @logger.levels.ERROR, "Failed to save client: #{error.message}", error
+          throw new z.client.ClientError z.client.ClientError::TYPE.DATABASE_FAILURE
       .then (client_payload) =>
         # Update cookie
         return @_transfer_cookie_label client_type, client_payload.cookie
@@ -355,23 +351,21 @@ class z.client.ClientRepository
   delete_client: (client_id, password) =>
     return new Promise (resolve, reject) =>
       if not password
-        error_message = "Could not delete client '#{client_id}' because password was not submitted"
-        @logger.log @logger.levels.ERROR, error_message
-        reject new z.client.ClientError error_message, z.client.ClientError::TYPE.REQUEST_FORBIDDEN
+        @logger.log @logger.levels.ERROR, "Could not delete client '#{client_id}' because password is missing"
+        reject new z.client.ClientError z.client.ClientError::TYPE.REQUEST_FORBIDDEN
 
       @client_service.delete_client client_id, password
       .then =>
         @_remove_client client_id
         resolve @clients()
       .catch (error) =>
-        error_message = "Unable to delete client '#{client_id}': #{error.message}"
-        @logger.log @logger.levels.ERROR, error_message,
+        @logger.log @logger.levels.ERROR, "Unable to delete client '#{client_id}': #{error.message}",
           {error: error, password: password}
 
         if error.code is z.service.BackendClientError::STATUS_CODE.FORBIDDEN
-          error = new z.client.ClientError error_message, z.client.ClientError::TYPE.REQUEST_FORBIDDEN
+          error = new z.client.ClientError z.client.ClientError::TYPE.REQUEST_FORBIDDEN
         else
-          error = new z.client.ClientError error_message, z.client.ClientError::TYPE.REQUEST_FAILURE
+          error = new z.client.ClientError z.client.ClientError::TYPE.REQUEST_FAILURE
         reject error
 
   ###
@@ -432,7 +426,7 @@ class z.client.ClientRepository
   @return [Boolean] Type of current client is permanent
   ###
   is_current_client_permanent: =>
-    throw new z.client.ClientError 'No current client', z.client.ClientError::TYPE.CLIENT_NOT_SET if not @current_client()
+    throw new z.client.ClientError z.client.ClientError::TYPE.CLIENT_NOT_SET if not @current_client()
     if z.util.Environment.electron
       is_permanent = true
     else
@@ -533,9 +527,9 @@ class z.client.ClientRepository
   @return [Boolean] Is the client the current local client
   ###
   _is_current_client: (user_id, client_id) ->
-    throw new z.client.ClientError 'No current client', z.client.ClientError::TYPE.CLIENT_NOT_SET if not @current_client()
-    throw new z.client.ClientError 'User ID is not defined', z.client.ClientError::TYPE.NO_USER_ID if not user_id
-    throw new z.client.ClientError 'Client ID is not defined', z.client.ClientError::TYPE.NO_CLIENT_ID if not client_id
+    throw new z.client.ClientError z.client.ClientError::TYPE.CLIENT_NOT_SET if not @current_client()
+    throw new z.client.ClientError z.client.ClientError::TYPE.NO_USER_ID if not user_id
+    throw new z.client.ClientError z.client.ClientError::TYPE.NO_CLIENT_ID if not client_id
     return user_id is @self_user().id and client_id is @current_client().id
 
   ###
diff --git a/app/script/components/asset/linkPreviewAsset.coffee b/app/script/components/asset/linkPreviewAsset.coffee
index 39b6b9e652f..d2ffe1ab57c 100644
--- a/app/script/components/asset/linkPreviewAsset.coffee
+++ b/app/script/components/asset/linkPreviewAsset.coffee
@@ -33,7 +33,7 @@ class z.components.LinkPreviewAssetComponent
     @url = @preview.original_url
 
   on_link_preview_click: =>
-    window.open @url
+    z.util.safe_window_open @url
 
   dispose: =>
     @element.removeEventListener 'click', @on_link_preview_click
@@ -57,7 +57,7 @@ ko.components.register 'link-preview-asset',
                 </span>
               <!-- /ko -->
               <div class="link-preview-title" data-bind="text: preview.title"></div>
-              <a class="link-preview-site text-graphite ellipsis" target="_blank" rel="nofollow"
+              <a class="link-preview-site text-graphite ellipsis" target="_blank" rel="nofollow noopener noreferrer"
                  data-bind="text: z.util.naked_url(url), attr: {href: url, title: url}"></a>
             </div>
             """
diff --git a/app/script/components/asset/locationAsset.coffee b/app/script/components/asset/locationAsset.coffee
index 680ef003d49..89ac6fefa0c 100644
--- a/app/script/components/asset/locationAsset.coffee
+++ b/app/script/components/asset/locationAsset.coffee
@@ -35,5 +35,5 @@ ko.components.register 'location-asset',
   template: """
             <div class="location-asset-icon icon-location"></div>
             <div class="location-asset-title" data-uie-name="location-name" data-bind="text: asset.name"></div>
-            <a target="_blank" class="label-xs text-theme" data-bind="attr: {href: asset.link_src}, l10n_text: z.string.conversation_location_link"></a>
+            <a target="_blank" rel="nofollow noopener noreferrer" class="label-xs text-theme" data-bind="attr: {href: asset.link_src}, l10n_text: z.string.conversation_location_link"></a>
             """
diff --git a/app/script/components/commonContacts.coffee b/app/script/components/commonContacts.coffee
index 7df158bea3b..40ee0809d12 100644
--- a/app/script/components/commonContacts.coffee
+++ b/app/script/components/commonContacts.coffee
@@ -31,10 +31,8 @@ class z.components.CommonContactsViewModel
     @_set_contacts_data 0
 
     @search_repository.get_common_contacts @user.id
-      .then (user_ets) =>
-        @_display_contacts user_ets
-      .catch (error) =>
-        @logger.log @logger.levels.ERROR, "Could not update users common contacts: #{error.message}", error
+    .then (user_ets) =>
+      @_display_contacts user_ets
 
   _set_contacts_data: (value) ->
     $(@element).attr 'data-contacts', value
diff --git a/app/script/connect/ConnectError.coffee b/app/script/connect/ConnectError.coffee
index 04f7153b343..aa4c6c291c3 100644
--- a/app/script/connect/ConnectError.coffee
+++ b/app/script/connect/ConnectError.coffee
@@ -20,11 +20,22 @@ window.z ?= {}
 z.connect ?= {}
 
 class z.connect.ConnectError
-  constructor: (message, type) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message
     @stack = (new Error()).stack
-    @type = type
+    @type = type or z.connect.ConnectError::TYPE.UNKNOWN
+
+    @message = switch @type
+      when z.connect.ConnectError::TYPE.GOOGLE_CLIENT
+        'Google Auth Client for JavaScript not loaded'
+      when z.connect.ConnectError::TYPE.GOOGLE_DOWNLOAD
+        'Failed to download contacts from Google'
+      when z.connect.ConnectError::TYPE.NO_CONTACTS
+        'No contacts found for matching'
+      when z.connect.ConnectError::TYPE.UPLOAD
+        'Address book upload failed'
+      else
+
 
   @:: = new Error()
   @::constructor = @
diff --git a/app/script/connect/ConnectGoogleService.coffee b/app/script/connect/ConnectGoogleService.coffee
index 739de94db7d..0d94ed648af 100644
--- a/app/script/connect/ConnectGoogleService.coffee
+++ b/app/script/connect/ConnectGoogleService.coffee
@@ -80,9 +80,8 @@ class z.connect.ConnectGoogleService
         else
           @_authenticate().then(resolve).catch reject
       else
-        error_message = 'Google Auth Client for JavaScript not loaded'
-        @logger.log @logger.levels.WARN, error_message
-        error = new z.connect.ConnectError error_message, z.connect.ConnectError::TYPE.GOOGLE_CLIENT
+        @logger.log @logger.levels.WARN, 'Google Auth Client for JavaScript not loaded'
+        error = new z.connect.ConnectError z.connect.ConnectError::TYPE.GOOGLE_CLIENT
         Raygun.send error
         reject error
 
diff --git a/app/script/connect/ConnectRepository.coffee b/app/script/connect/ConnectRepository.coffee
index b392f4c9e8c..60e5ba00b04 100644
--- a/app/script/connect/ConnectRepository.coffee
+++ b/app/script/connect/ConnectRepository.coffee
@@ -39,19 +39,14 @@ class z.connect.ConnectRepository
     return new Promise (resolve, reject) =>
       @connect_google_service.get_contacts()
       .catch (error) =>
-        error_message = 'Google Contacts SDK error'
-        @logger.log @logger.levels.INFO, error_message, error
-        connect_error = new z.connect.ConnectError error_message, z.connect.ConnectError::TYPE.GOOGLE_DOWNLOAD
-        reject connect_error
-        throw connect_error
+        @logger.log @logger.levels.INFO, 'Google Contacts SDK error', error
+        throw new z.connect.ConnectError z.connect.ConnectError::TYPE.GOOGLE_DOWNLOAD
       .then (response) =>
         return @_parse_google_contacts response
       .then (phone_book) =>
         if phone_book.cards.length is 0
-          error_message = 'No contacts found for upload'
-          @logger.log @logger.levels.WARN, error_message
-          resolve []
-          throw new z.connect.ConnectError error_message, z.connect.ConnectError::TYPE.NO_CONTACTS
+          @logger.log @logger.levels.WARN, 'No contacts found for upload'
+          throw new z.connect.ConnectError z.connect.ConnectError::TYPE.NO_CONTACTS
         else
           @logger.log @logger.levels.INFO, "Uploading hashes of '#{phone_book.cards.length}' contacts for matching", phone_book
           return @connect_service.post_onboarding phone_book
@@ -61,15 +56,19 @@ class z.connect.ConnectRepository
         @user_repository.save_property_contact_import_google Date.now()
         resolve response
       .catch (error) =>
-        if error not instanceof z.connect.ConnectError
+        if error instanceof z.connect.ConnectError
+          switch error.type
+            when z.connect.ConnectError::TYPE.GOOGLE_DOWNLOAD
+              reject error
+            when z.connect.ConnectError::TYPE.NO_CONTACTS
+              resolve []
+        else
           if error.code is z.service.BackendClientError::STATUS_CODE.TOO_MANY_REQUESTS
             error_message = 'Backend refused Gmail contacts upload: Endpoint used too frequent'
             @logger.log @logger.levels.ERROR, error_message
           else
-            error_message = 'Gmail contacts upload failed'
-            @logger.log @logger.levels.ERROR, error_message, error
-          reject new z.connect.ConnectError error_message, z.connect.ConnectError::TYPE.UPLOAD
-
+            @logger.log @logger.levels.ERROR, 'Gmail contacts upload failed', error
+          reject new z.connect.ConnectError z.connect.ConnectError::TYPE.UPLOAD
 
   ###
   Retrieve a user's OSX address book contacts.
@@ -80,9 +79,8 @@ class z.connect.ConnectRepository
       phone_book = @_parse_osx_contacts()
 
       if phone_book.cards.length is 0
-        error_message = 'No contacts found for upload'
-        @logger.log @logger.levels.WARN, error_message
-        reject new z.connect.ConnectError 'No contacts found for upload', z.connect.ConnectError::TYPE.NO_CONTACTS
+        @logger.log @logger.levels.WARN, 'No contacts found for upload'
+        reject new z.connect.ConnectError z.connect.ConnectError::TYPE.NO_CONTACTS
       else
         @logger.log @logger.levels.INFO, "Uploading hashes of '#{phone_book.cards.length}' contacts for matching", phone_book
         @connect_service.post_onboarding phone_book
@@ -96,9 +94,8 @@ class z.connect.ConnectRepository
             error_message = 'Backend refused OS X contacts upload: Endpoint used too frequent'
             @logger.log @logger.levels.ERROR, error_message
           else
-            error_message = 'OS X contacts upload failed'
-            @logger.log @logger.levels.ERROR, error_message, error
-          reject new z.connect.ConnectError error_message, z.connect.ConnectError::TYPE.UPLOAD
+            @logger.log @logger.levels.ERROR, 'OS X contacts upload failed', error
+          reject new z.connect.ConnectError z.connect.ConnectError::TYPE.UPLOAD
 
   ###
   Encode phone book
diff --git a/app/script/conversation/ConversationError.coffee b/app/script/conversation/ConversationError.coffee
new file mode 100644
index 00000000000..595e6d132c2
--- /dev/null
+++ b/app/script/conversation/ConversationError.coffee
@@ -0,0 +1,44 @@
+#
+# Wire
+# Copyright (C) 2016 Wire Swiss GmbH
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+#
+
+window.z ?= {}
+z.conversation ?= {}
+
+class z.conversation.ConversationError
+  constructor: (type) ->
+    @name = @constructor.name
+    @stack = (new Error()).stack
+    @type = type or z.conversation.ConversationError::TYPE.UNKNOWN
+
+    @message = switch @type
+      when z.conversation.ConversationError::TYPE.MESSAGE_NOT_FOUND
+        'Message not found'
+      when z.conversation.ConversationError::TYPE.NO_CHANGES
+        'Missing changes to message'
+      when z.conversation.ConversationError::TYPE.WRONG_USER
+        'Wrong user tried to change or delete a message'
+      else
+        'Unknown ConversationError'
+
+  @:: = new Error()
+  @::constructor = @
+  @::TYPE =
+    MESSAGE_NOT_FOUND: 'z.conversation.ConversationError::TYPE.MESSAGE_NOT_FOUND'
+    NO_CHANGES: 'z.conversation.ConversationError::TYPE.NO_CHANGES'
+    WRONG_USER: 'z.conversation.ConversationError::TYPE.WRONG_USER'
+    UNKNOWN: 'z.conversation.ConversationError::TYPE.UNKNOWN'
diff --git a/app/script/conversation/ConversationRepository.coffee b/app/script/conversation/ConversationRepository.coffee
index 5c8262d1699..4c798b3fd3c 100644
--- a/app/script/conversation/ConversationRepository.coffee
+++ b/app/script/conversation/ConversationRepository.coffee
@@ -38,16 +38,16 @@ class z.conversation.ConversationRepository
     @event_mapper = new z.conversation.EventMapper @asset_service, @user_repository
 
     @active_conversation = ko.observable()
-
     @conversations = ko.observableArray []
-    @has_initialized_participants = false
-    @is_handling_notifications = true
+
+    @block_event_handling = true
     @fetching_conversations = {}
+    @has_initialized_participants = false
 
-    @self_conversation = ko.computed =>
+    @self_conversation = ko.pureComputed =>
       return @find_conversation_by_id @user_repository.self().id if @user_repository.self()
 
-    @filtered_conversations = ko.computed =>
+    @filtered_conversations = ko.pureComputed =>
       @conversations().filter (conversation_et) ->
         states_to_filter = [z.user.ConnectionStatus.BLOCKED, z.user.ConnectionStatus.CANCELLED, z.user.ConnectionStatus.PENDING]
         return false if conversation_et.connection().status() in states_to_filter
@@ -55,9 +55,15 @@ class z.conversation.ConversationRepository
         return false if conversation_et.is_cleared() and conversation_et.removed_from_conversation()
         return true
 
-    @sorted_conversations = ko.computed =>
+    @sorted_conversations = ko.pureComputed =>
       @filtered_conversations().sort z.util.sort_groups_by_last_event
 
+    @sending_promises = []
+    @sending_queue = ko.observableArray []
+    @sending_blocked = false
+
+    @sending_queue.subscribe @_execute_from_sending_queue
+
     @conversations_archived = ko.observableArray []
     @conversations_call = ko.observableArray []
     @conversations_cleared = ko.observableArray []
@@ -98,8 +104,42 @@ class z.conversation.ConversationRepository
     amplify.subscribe z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, @set_notification_handling_state
     amplify.subscribe z.event.WebApp.SELF.CLIENT_ADD, @on_self_client_add
     amplify.subscribe z.event.WebApp.USER.UNBLOCKED, @unblocked_user
-    amplify.subscribe z.event.WebApp.CONVERSATION.MESSAGE.DELETE_SELF, @delete_message
-    amplify.subscribe z.event.WebApp.CONVERSATION.MESSAGE.DELETE_EVERYONE, @delete_message_everyone
+
+  ###
+  Adds a generic message to a the sending queue.
+
+  @private
+  @param conversation_id [String] Conversation ID
+  @param generic_message [z.protobuf.GenericMessage] Protobuf message to be encrypted and send
+  @param user_ids [Array<String>] Optional array of user IDs to limit sending to
+  @return [Promise] Promise that resolves when the message was sent
+  ###
+  _add_to_sending_queue: (conversation_id, generic_message, user_ids) =>
+    return new Promise (resolve, reject) =>
+      queue_entry =
+        function: => @_send_generic_message conversation_id, generic_message, user_ids
+        resolve: resolve
+        reject: reject
+
+      @sending_queue.push queue_entry
+
+  ###
+  Sends a generic message from the sending queue.
+  @private
+  ###
+  _execute_from_sending_queue: =>
+    return if @block_event_handling or @sending_blocked
+
+    queue_entry = @sending_queue()[0]
+    if queue_entry
+      @sending_blocked = true
+      queue_entry.function()
+      .catch (error) ->
+        queue_entry.reject error
+      .then (response) =>
+        queue_entry.resolve response if response
+        @sending_blocked = false
+        @sending_queue.shift()
 
 
   ###############################################################################
@@ -118,7 +158,7 @@ class z.conversation.ConversationRepository
   create_new_conversation: (user_ids, name, on_success, on_error) =>
     @conversation_service.create_conversation user_ids, name, (response, error) =>
       if response
-        on_success? @create response
+        on_success? @_on_create response
       else
         on_error? error
 
@@ -179,21 +219,24 @@ class z.conversation.ConversationRepository
   @param message_id [String]
   @return [Promise] z.entity.Message
   ###
-  get_message_from_db: (conversation_et, message_id) =>
-    @conversation_service.load_event_from_db conversation_et.id, message_id
+  get_message_in_conversation_by_id: (conversation_et, message_id) =>
+    message_et = conversation_et.get_message_by_id message_id
+    return Promise.resolve message_et if message_et
+
+    return @conversation_service.load_event_from_db conversation_et.id, message_id
     .then (event) =>
-      raw_event = event.mapped or event.raw
-      return @event_mapper.map_json_event raw_event, conversation_et
+      if event
+        return @event_mapper.map_json_event event, conversation_et
+      throw new z.conversation.ConversationError z.conversation.ConversationError::TYPE.MESSAGE_NOT_FOUND
 
   get_events: (conversation_et) ->
     return new Promise (resolve, reject) =>
       conversation_et.is_pending true
       timestamp = conversation_et.get_first_message()?.timestamp
-
-      @conversation_service.load_events_from_db conversation_et.id, timestamp
-      .then (loaded_events) =>
-        [events, has_further_events] = loaded_events
-        conversation_et.has_further_messages has_further_events
+      @conversation_service.load_events_from_db conversation_et.id, timestamp, null, z.config.MESSAGES_FETCH_LIMIT
+      .then (events) =>
+        if events.length < z.config.MESSAGES_FETCH_LIMIT
+          conversation_et.has_further_messages false
         if events.length is 0
           @logger.log @logger.levels.INFO, "No events for conversation '#{conversation_et.id}' found", events
         else if timestamp
@@ -203,8 +246,7 @@ class z.conversation.ConversationRepository
         else
           @logger.log @logger.levels.INFO,
             "Loaded first #{events.length} event(s) for conversation '#{conversation_et.id}'", events
-        raw_events = (event.mapped or event.raw for event in events)
-        mapped_messages = @_add_events_to_conversation events: raw_events, conversation_et
+        mapped_messages = @_add_events_to_conversation events: events, conversation_et
         conversation_et.is_pending false
         resolve mapped_messages
       .catch (error) =>
@@ -218,11 +260,10 @@ class z.conversation.ConversationRepository
   _get_unread_events: (conversation_et) ->
     conversation_et.is_pending true
     timestamp = conversation_et.get_first_message()?.timestamp
-    @conversation_service.load_unread_events_from_db conversation_et, timestamp
+    @conversation_service.load_events_from_db conversation_et.id, timestamp, conversation_et.last_read_timestamp()
     .then (events) =>
       if events.length
-        raw_events = (event.mapped or event.raw for event in events)
-        @_add_events_to_conversation events: raw_events, conversation_et
+        @_add_events_to_conversation events: events, conversation_et
       conversation_et.is_pending false
     .catch (error) =>
       @logger.log @logger.levels.INFO, "Could not load unread events for conversation: #{conversation_et.id}", error
@@ -278,7 +319,7 @@ class z.conversation.ConversationRepository
   ###
   get_conversation_by_id: (conversation_id, callback) ->
     if not conversation_id
-      Raygun.send new Error 'Trying to get conversation without ID'
+      throw new Error 'Trying to get conversation without ID'
       return
 
     conversation_et = @find_conversation_by_id conversation_id
@@ -410,7 +451,7 @@ class z.conversation.ConversationRepository
   ###
   mark_as_read: (conversation_et) =>
     return if conversation_et is undefined
-    return if @is_handling_notifications
+    return if @block_event_handling
     return if conversation_et.number_of_unread_events() is 0
     return if conversation_et.get_last_message()?.type is z.event.Backend.CONVERSATION.MEMBER_UPDATE
 
@@ -439,11 +480,12 @@ class z.conversation.ConversationRepository
   ###
   Set the notification handling state.
   @note Temporarily do not unarchive conversations when handling the notification stream
-  @param handling_notifications [Boolean] Notifications are being handled from the stream
+  @param handling_state [z.event.NotificationHandlingState] State of the notifications stream handling
   ###
-  set_notification_handling_state: (handling_notifications) =>
-    @is_handling_notifications = handling_notifications
-    @logger.log @logger.levels.INFO, "Ignoring events for unarchiving: #{handling_notifications}"
+  set_notification_handling_state: (handling_state) =>
+    @block_event_handling = handling_state isnt z.event.NotificationHandlingState.WEB_SOCKET
+    @_execute_from_sending_queue()
+    @logger.log @logger.levels.INFO, "Block handling of conversation events: #{@block_event_handling}"
 
   ###
   Update participating users in a conversation.
@@ -482,7 +524,7 @@ class z.conversation.ConversationRepository
       callback?()
     .catch (error_response) ->
       if error_response.label is z.service.BackendClientError::LABEL.TOO_MANY_MEMBERS
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.TOO_MANY_MEMBERS,
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.TOO_MANY_MEMBERS,
           data:
             max: z.config.MAXIMUM_CONVERSATION_SIZE
             open_spots: Math.max 0, z.config.MAXIMUM_CONVERSATION_SIZE - (conversation_et.number_of_participants() + 1)
@@ -502,7 +544,7 @@ class z.conversation.ConversationRepository
 
     @conversation_service.update_member_properties conversation_et.id, payload
     .then =>
-      @member_update conversation_et, {data: payload}, next_conversation_et
+      @_on_member_update conversation_et, {data: payload}, next_conversation_et
       @logger.log @logger.levels.INFO,
         "Archived conversation '#{conversation_et.id}' on '#{payload.otr_archived_ref}'"
     .catch (error) =>
@@ -539,7 +581,7 @@ class z.conversation.ConversationRepository
       generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
       generic_message.set 'cleared', message_content
 
-      @_send_generic_message @self_conversation().id, generic_message
+      @_add_to_sending_queue @self_conversation().id, generic_message
       .then =>
         @logger.log @logger.levels.INFO,
           "Cleared conversation '#{conversation_et.id}' as read on '#{new Date(cleared_timestamp).toISOString()}'"
@@ -559,7 +601,7 @@ class z.conversation.ConversationRepository
     @conversation_service.delete_members conversation_et.id, @user_repository.self().id
     .then (response) =>
       amplify.publish z.event.WebApp.EVENT.INJECT, response
-      @member_leave conversation_et, response
+      @_on_member_leave conversation_et, response
     .then =>
       if callback?
         callback next_conversation_et
@@ -667,7 +709,7 @@ class z.conversation.ConversationRepository
       @conversation_service.update_member_properties conversation_et.id, payload
       .then =>
         response = {data: payload}
-        @member_update conversation_et, response
+        @_on_member_update conversation_et, response
         @logger.log @logger.levels.INFO,
           "Toggle silence to '#{payload.otr_muted}' for conversation '#{conversation_et.id}' on '#{payload.otr_muted_ref}'"
         resolve response
@@ -690,7 +732,7 @@ class z.conversation.ConversationRepository
       @conversation_service.update_member_properties conversation_et.id, payload
       .then =>
         response = {data: payload}
-        @member_update conversation_et, response
+        @_on_member_update conversation_et, response
         @logger.log @logger.levels.INFO,
           "Unarchived conversation '#{conversation_et.id}' on '#{payload.otr_archived_ref}'"
         callback?()
@@ -716,7 +758,7 @@ class z.conversation.ConversationRepository
       generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
       generic_message.set 'lastRead', message_content
 
-      @_send_generic_message @self_conversation().id, generic_message
+      @_add_to_sending_queue @self_conversation().id, generic_message
       .then =>
         @logger.log @logger.levels.INFO,
           "Marked conversation '#{conversation_et.id}' as read on '#{new Date(timestamp).toISOString()}'"
@@ -732,61 +774,29 @@ class z.conversation.ConversationRepository
 
   ###
   Send encrypted assets. Used for file transfers.
-
-  # TODO unify with image asset
-  # create and send original proto message (message-add)
-  # create and send uploaded proto message with status (asset-add)
-
   @param conversation_id [String] Conversation ID
   @return [Object] Collection with User IDs which hold their Client IDs in an Array
   ###
   send_asset: (conversation_et, file, nonce) =>
-    conversation_id = conversation_et.id
     generic_message = null
-    key_bytes = null
-    sha256 = null
-    ciphertext = null
-    body_payload = null
-    initial_payload = null
-
-    return Promise.resolve()
-    .then ->
+    Promise.resolve()
+    .then =>
       message_et = conversation_et.get_message_by_id nonce
       asset_et = message_et.assets()[0]
       asset_et.upload_id nonce # TODO combine
       asset_et.uploaded_on_this_client true
-
-      return z.util.load_file_buffer file
-    .then (file_bytes) ->
-      return z.assets.AssetCrypto.encrypt_aes_asset file_bytes
-    .then (data) ->
-      # TODO send original message and
-      [key_bytes, sha256, ciphertext] = data
-      key_bytes = new Uint8Array key_bytes
-      sha256 = new Uint8Array sha256
-    .then =>
-      return @_create_user_client_map conversation_id
-    .then (user_client_map) =>
+      return @asset_service.create_asset_proto file
+    .then ([asset, ciphertext]) =>
       generic_message = new z.proto.GenericMessage nonce
-      generic_message.set 'asset', @_construct_asset_uploaded key_bytes, sha256
-      return @cryptography_repository.encrypt_generic_message user_client_map, generic_message
-    .then (payload) =>
-      payload.inline = false
-      payload.native_push = true
-      body_payload = new Uint8Array ciphertext
-      initial_payload = payload
-      return @asset_service.post_asset_v2 conversation_id, payload, body_payload, false, nonce
-    .catch (error_response) =>
-      return @_update_payload_for_changed_clients error_response, generic_message, initial_payload
-      .then (updated_payload) =>
-        @asset_service.post_asset_v2 conversation_id, updated_payload, body_payload, true, nonce
+      generic_message.set 'asset', asset
+      @_send_encrypted_asset conversation_et.id, generic_message, ciphertext, nonce
     .then (response) =>
       [json, asset_id] = response
       event = @_construct_otr_asset_event response, conversation_et.id, asset_id
-      event.data.otr_key = key_bytes
-      event.data.sha256 = sha256
+      event.data.otr_key = generic_message.asset.uploaded.otr_key
+      event.data.sha256 = generic_message.asset.uploaded.sha256
       event.id = nonce
-      return @asset_upload_complete conversation_et, event
+      return @_on_asset_upload_complete conversation_et, event
 
   ###
   When we reset a session then we must inform the remote client about this action.
@@ -795,8 +805,10 @@ class z.conversation.ConversationRepository
   @param file [File] File to send
   ###
   send_asset_metadata: (conversation_et, file) =>
+    asset = new z.proto.Asset()
+    asset.set 'original', new z.proto.Asset.Original file.type, file.size, file.name
     generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
-    generic_message.set 'asset', @_construct_asset_original file
+    generic_message.set 'asset', asset
     @_send_and_save_generic_message conversation_et, generic_message
 
   ###
@@ -807,57 +819,55 @@ class z.conversation.ConversationRepository
   @param reason [z.assets.AssetUploadFailedReason] cause for the failed upload (optional)
   ###
   send_asset_upload_failed: (conversation_et, nonce, reason = z.assets.AssetUploadFailedReason.FAILED) =>
+    reason_proto = if reason is z.assets.AssetUploadFailedReason.CANCELLED then z.proto.Asset.NotUploaded.CANCELLED else z.proto.Asset.NotUploaded.FAILED
+    asset = new z.proto.Asset()
+    asset.set 'not_uploaded', reason_proto
     generic_message = new z.proto.GenericMessage nonce
-    generic_message.set 'asset', @_construct_asset_not_uploaded reason
+    generic_message.set 'asset', asset
     @_send_and_save_generic_message conversation_et, generic_message
 
+  ###
+  Send a confirmation for a content message.
+  @param conversation [z.entity.Conversation] Conversation that content message was received in
+  @param message_et [String] ID of message for which to acknowledge receipt
+  ###
+  send_confirmation_status: (conversation_et, message_et) =>
+    return # temporarily disable confirmation messages
+    return if message_et.user().is_me or not conversation_et.is_one2one() or message_et.type not in z.event.EventTypeHandling.CONFIRM
+
+    generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
+    generic_message.set 'confirmation', new z.proto.Confirmation message_et.id, z.proto.Confirmation.Type.DELIVERED
+    @_add_to_sending_queue conversation_et.id, generic_message, [message_et.user().id]
+
   ###
   Sends an OTR Image Asset
   ###
   send_image_asset: (conversation_et, image) =>
-    return new Promise (resolve, reject) =>
-      asset = null
-      ciphertext = null
-      conversation_id = conversation_et.id
-      generic_message = null
-      initial_payload = null
-
-      @asset_service.create_asset_proto image
-      .then ([asset, asset_ciphertext]) =>
-        ciphertext = asset_ciphertext
-        generic_message = new z.proto.GenericMessage z.util.create_random_uuid(), null, asset
-        return @_create_user_client_map conversation_id
-      .then (user_client_map) =>
-        return @cryptography_repository.encrypt_generic_message user_client_map, generic_message
-      .then (payload) =>
-        initial_payload = payload
-        initial_payload.inline = false
-        initial_payload.native_push = true
-        return @asset_service.post_asset_v2 conversation_id, initial_payload, ciphertext, false
-      .catch (error_response) =>
-        return @_update_payload_for_changed_clients error_response, generic_message, initial_payload
-        .then (updated_payload) =>
-          @asset_service.post_asset_v2 conversation_id, updated_payload, ciphertext, true
-      .then ([json, asset_id]) =>
-        amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.SessionEventName.INTEGER.IMAGE_SENT
-        amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.MEDIA.COMPLETED_MEDIA_ACTION, {
-          action: 'photo'
-          conversation_type: z.tracking.helpers.get_conversation_type conversation_et
-          with_bot: conversation_et.is_with_bot()
-        }
-        event = @_construct_otr_asset_event json, conversation_id, asset_id
-        return @cryptography_repository.save_encrypted_event generic_message, event
-      .then (record) =>
-        @add_event conversation_et, record.mapped
-        resolve()
-      .catch (error) =>
-        @logger.log "Failed to upload otr asset for conversation #{conversation_id}", error
-        exception = new Error('Event response is undefined')
-        custom_data =
-          source: 'Sending medium image'
-          error: error
-        Raygun.send exception, custom_data
-        reject error
+    generic_message = null
+    @asset_service.create_image_proto image
+    .then ([image, ciphertext]) =>
+      generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
+      generic_message.set 'image', image
+      return @_send_encrypted_asset conversation_et.id, generic_message, ciphertext
+    .then ([json, asset_id]) =>
+      amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.SessionEventName.INTEGER.IMAGE_SENT
+      amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.MEDIA.COMPLETED_MEDIA_ACTION, {
+        action: 'photo'
+        conversation_type: z.tracking.helpers.get_conversation_type conversation_et
+        with_bot: conversation_et.is_with_bot()
+      }
+      event = @_construct_otr_asset_event json, conversation_et.id, asset_id
+      return @cryptography_repository.save_encrypted_event generic_message, event
+    .then (record) =>
+      @_on_add_event conversation_et, record
+    .catch (error) =>
+      @logger.log "Failed to upload otr asset for conversation #{conversation_et.id}", error
+      exception = new Error('Event response is undefined')
+      custom_data =
+        source: 'Sending medium image'
+        error: error
+      Raygun.send exception, custom_data
+      throw error
 
   ###
   Send an encrypted knock.
@@ -946,12 +956,12 @@ class z.conversation.ConversationRepository
       generic_message.set 'edited', new z.proto.MessageEdit original_message_et.id, new z.proto.Text message
       return generic_message
     .then (generic_message) =>
-      @_send_generic_message conversation_et.id, generic_message
+      @_add_to_sending_queue conversation_et.id, generic_message
     .then (response) =>
       event = @_construct_otr_message_event response, conversation_et.id
       return @cryptography_repository.save_encrypted_event generic_message, event
     .then (record) =>
-      @on_conversation_event record.mapped if record?.mapped
+      @on_conversation_event record
     .then =>
       @_track_edit_message conversation_et, original_message_et
     .then =>
@@ -964,6 +974,22 @@ class z.conversation.ConversationRepository
       @logger.log @logger.levels.ERROR, "Error while editing message: #{error.message}", error
       throw error
 
+  ###
+  Send a reaction to a content message.
+  @param conversation [z.entity.Conversation] Conversation that content message was received in
+  @param message_et [String] ID of message for react to
+  @param reaction [z.message.ReactionType]
+  ###
+  send_reaction: (conversation_et, message_et, reaction) =>
+    generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
+    generic_message.set 'reaction', new z.proto.Reaction reaction, message_et.id
+    @_add_to_sending_queue conversation_et.id, generic_message
+    .then (response) =>
+      event = @_construct_otr_message_event response, conversation_et.id
+      return @cryptography_repository.cryptography_mapper.map_generic_message generic_message, event
+    .then (mapped_event) =>
+      @on_conversation_event mapped_event
+
   ###
   Sending a message to the remote end of a session reset.
 
@@ -993,48 +1019,6 @@ class z.conversation.ConversationRepository
         @logger.log @logger.levels.ERROR, "Sending conversation reset failed: #{error.message}", error
         reject error
 
-  ###
-  Create not uploaded Asset protobuf message (failure).
-
-  @private
-  @param reason [z.assets.AssetUploadFailedReason] Conversation ID
-  @return [z.proto.Asset] Asset protobuf message
-  ###
-  _construct_asset_not_uploaded: (reason) ->
-    asset = new z.proto.Asset()
-    if reason is z.assets.AssetUploadFailedReason.CANCELLED
-      asset.set 'not_uploaded', z.proto.Asset.NotUploaded.CANCELLED
-    else
-      asset.set 'not_uploaded', z.proto.Asset.NotUploaded.FAILED
-    return asset
-
-  ###
-  Create original Asset protobuf message.
-
-  @private
-  @param file [Object] File data
-  @return [z.proto.Asset] Asset protobuf message
-  ###
-  _construct_asset_original: (file) ->
-    original_asset = new z.proto.Asset.Original file.type, file.size, file.name
-    asset = new z.proto.Asset()
-    asset.set 'original', original_asset
-    return asset
-
-  ###
-  Create uploaded Asset proto (success).
-
-  @private
-  @param otr_key [ByteArray] Encryption key
-  @param sha256 [ByteArray] Sha256
-  @return [z.proto.Asset] Asset protobuf message
-  ###
-  _construct_asset_uploaded: (otr_key, sha256) ->
-    uploaded_asset = new z.proto.Asset.RemoteData otr_key, sha256
-    asset = new z.proto.Asset()
-    asset.set 'uploaded', uploaded_asset
-    return asset
-
   ###
   Construct an encrypted message event.
 
@@ -1103,6 +1087,10 @@ class z.conversation.ConversationRepository
     user_client_map[user_id] = [client_id]
     return user_client_map
 
+  _execute_message_queue: ->
+    @send_confirmation_status conversation_et, message_et for [conversation_et, message_et] in @sending_queue
+    @sending_queue = []
+
   ###############################################################################
   # Send Generic Messages
   ###############################################################################
@@ -1123,7 +1111,7 @@ class z.conversation.ConversationRepository
       if @_send_as_external_message conversation_et, generic_message
         @_send_external_generic_message conversation_et.id, generic_message
       else
-        @_send_generic_message conversation_et.id, generic_message
+        @_add_to_sending_queue conversation_et.id, generic_message
     .catch (error) =>
       if error.code is z.service.BackendClientError::STATUS_CODE.REQUEST_TOO_LARGE
         return @_send_external_generic_message conversation_et.id, generic_message
@@ -1132,7 +1120,7 @@ class z.conversation.ConversationRepository
       event = @_construct_otr_message_event response, conversation_et.id
       return @cryptography_repository.save_encrypted_event generic_message, event
     .then (record) =>
-      @add_event conversation_et, record.mapped if record?.mapped
+      @_on_add_event conversation_et, record
       return record
     .catch (error) =>
       error_message = "Could not send OTR message of type '#{generic_message.content}' to conversation ID '#{conversation_et.id}' (#{conversation_et.display_name()}): #{error.message}"
@@ -1182,28 +1170,34 @@ class z.conversation.ConversationRepository
   @private
   @param conversation_id [String] Conversation ID
   @param generic_message [z.protobuf.GenericMessage] Protobuf message to be encrypted and send
-  @return [Promise] Promise that resolves after sending the encrypted message
+  @param user_ids [Array<String>] Optional array of user IDs to limit sending to
+  @return [Promise] Promise that resolves when the message was sent
   ###
-  _send_generic_message: (conversation_id, generic_message) =>
+  _send_generic_message: (conversation_id, generic_message, user_ids) =>
     @_create_user_client_map conversation_id
     .then (user_client_map) =>
+      if user_ids
+        delete user_client_map[user_id] for user_id of user_client_map when user_id not in user_ids
       return @cryptography_repository.encrypt_generic_message user_client_map, generic_message
     .then (payload) =>
-      @_send_encrypted_message conversation_id, generic_message, payload
+      @_send_encrypted_message conversation_id, generic_message, payload, user_ids
 
   ###
   Sends otr message to a conversation.
 
   @private
+  @note Options for the precondition check on missing clients are:
+    'false' - all clients, 'Array<String>' - only clients of listed users, 'true' - force sending
   @param conversation_id [String] Conversation ID
   @param generic_message [z.protobuf.GenericMessage] Protobuf message to be encrypted and send
   @param payload [Object]
+  @param precondition_option [Array<String>|Boolean] Level that backend checks for missing clients
   @return [Promise] Promise that resolves after sending the encrypted message
   ###
-  _send_encrypted_message: (conversation_id, generic_message, payload) =>
+  _send_encrypted_message: (conversation_id, generic_message, payload, precondition_option = false) =>
     @logger.log @logger.levels.INFO,
       "Sending encrypted '#{generic_message.content}' message to conversation '#{conversation_id}'", payload
-    @conversation_service.post_encrypted_message conversation_id, payload, false
+    @conversation_service.post_encrypted_message conversation_id, payload, precondition_option
     .catch (error_response) =>
       return @_update_payload_for_changed_clients error_response, generic_message, payload
       .then (updated_payload) =>
@@ -1211,6 +1205,29 @@ class z.conversation.ConversationRepository
           "Sending updated encrypted '#{generic_message.content}' message to conversation '#{conversation_id}'", updated_payload
         return @conversation_service.post_encrypted_message conversation_id, updated_payload, true
 
+  ###
+  Sends otr asset to a conversation.
+
+  @private
+  @param conversation_id [String] Conversation ID
+  @param generic_message [z.protobuf.GenericMessage] Protobuf message to be encrypted and send
+  @param image_data [Uint8Array|ArrayBuffer]
+  @param nonce [String]
+  @return [Promise] Promise that resolves after sending the encrypted message
+  ###
+  _send_encrypted_asset: (conversation_id, generic_message, image_data, nonce) =>
+    @_create_user_client_map conversation_id
+    .then (user_client_map) =>
+      return @cryptography_repository.encrypt_generic_message user_client_map, generic_message
+    .then (payload) =>
+      payload.inline = false
+      payload.native_push = true
+      @asset_service.post_asset_v2 conversation_id, payload, image_data, false, nonce
+      .catch (error_response) =>
+        return @_update_payload_for_changed_clients error_response, generic_message, payload
+        .then (updated_payload) =>
+          @asset_service.post_asset_v2 conversation_id, updated_payload, image_data, true, nonce
+
   ###
   Estimate whether message should be send as type external.
 
@@ -1270,15 +1287,15 @@ class z.conversation.ConversationRepository
 
     @send_asset_metadata conversation_et, file
     .then (record) =>
-      message_et = conversation_et.get_message_by_id record.mapped.id
-      @send_asset conversation_et, file, record.mapped.id
+      message_et = conversation_et.get_message_by_id record.id
+      @send_asset conversation_et, file, record.id
     .then =>
       upload_duration = (Date.now() - upload_started) / 1000
       @logger.log "Finished to upload asset for conversation'#{conversation_et.id} in #{upload_duration}"
       amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.FILE.UPLOAD_SUCCESSFUL,
         $.extend tracking_data, {time: upload_duration}
     .catch (error) =>
-      @logger.log "Failed to upload asset for conversation'#{conversation_et.id}", error
+      @logger.log "Failed to upload asset for conversation '#{conversation_et.id}", error
       if message_et.id
         @send_asset_upload_failed conversation_et, message_et.id
         @update_message_as_upload_failed message_et
@@ -1294,18 +1311,18 @@ class z.conversation.ConversationRepository
     Promise.resolve()
     .then ->
       if not message_et.user().is_me
-        throw new Error 'Cannot delete other users message'
+        throw new z.conversation.ConversationError z.conversation.ConversationError::TYPE.WRONG_USER
       generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
       generic_message.set 'deleted', new z.proto.MessageDelete message_et.id
       return generic_message
     .then (generic_message) =>
-      @_send_generic_message conversation_et.id, generic_message
+      @_add_to_sending_queue conversation_et.id, generic_message
     .then =>
       @_track_delete_message conversation_et, message_et, z.tracking.attribute.DeleteType.EVERYWHERE
     .then =>
-      return @_delete_message conversation_et, message_et.id
+      return @_delete_message_by_id conversation_et, message_et.id
     .catch (error) =>
-      @logger.log "Failed to send delete message for everyone with id '#{message_id}' for conversation '#{conversation_et.id}'", error
+      @logger.log "Failed to send delete message for everyone with id '#{message_et.id}' for conversation '#{conversation_et.id}'", error
       throw error
 
   ###
@@ -1321,13 +1338,13 @@ class z.conversation.ConversationRepository
       generic_message.set 'hidden', new z.proto.MessageHide conversation_et.id, message_et.id
       return generic_message
     .then (generic_message) =>
-      @_send_generic_message @self_conversation().id, generic_message
+      @_add_to_sending_queue @self_conversation().id, generic_message
     .then =>
       @_track_delete_message conversation_et, message_et, z.tracking.attribute.DeleteType.LOCAL
     .then =>
-      return @_delete_message conversation_et, message_et.id
+      return @_delete_message_by_id conversation_et, message_et.id
     .catch (error) =>
-      @logger.log "Failed to send delete message with id '#{message_id}' for conversation '#{conversation_et.id}'", error
+      @logger.log "Failed to send delete message with id '#{message_et.id}' for conversation '#{conversation_et.id}'", error
       throw error
 
   ###
@@ -1377,112 +1394,126 @@ class z.conversation.ConversationRepository
   ###############################################################################
 
   ###
-  A text message received in a conversation.
-  @param conversation_et [z.entity.Conversation] Conversation to add the event to
-  @param event_json [Object] JSON data of 'conversation.message-add'
-  ###
-  message_added: (conversation_et, event_json) =>
-    Promise.resolve()
-    .then =>
-      if event_json.data.replacing_message_id
-        return @_update_edited_message conversation_et, event_json
-      return event_json
-    .then (updated_event_json) =>
-      if event_json.data.replacing_message_id
-        @_delete_message conversation_et, event_json.data.replacing_message_id
-      @add_event conversation_et, updated_event_json
+  Listener for incoming events from the WebSocket.
 
-  ###
-  A hide message received in a conversation.
-  @param event_json [Object] JSON data of 'conversation.message-hidden'
-  ###
-  message_hidden: (event_json) =>
-    Promise.resolve()
-    .then =>
-      if event_json.from isnt @user_repository.self().id
-        throw new Error 'Sender is not self user'
-      return @find_conversation_by_id event_json.data.conversation_id
-    .then (conversation_et) =>
-      return @_delete_message conversation_et, event_json.data.message_id
-    .catch (error) =>
-      @logger.log "Failed to delete message for conversation '#{conversation_et.id}'", error
-      throw error
+  @private
+  @note We check for events received multiple times via the WebSocket by event id here
+  @param event [Object] JSON data for event
+  ####
+  on_conversation_event: (event) =>
+    if not event
+      error = new Error('Event response is undefined')
+      custom_data =
+        source: 'WebSocket'
+      Raygun.send error, custom_data
 
-  ###
-  A hide message received in a conversation.
-  @param conversation_et [z.entity.Conversation] Conversation to add the event to
-  @param event_json [Object] JSON data of 'conversation.message-delete'
-  ###
-  message_deleted: (conversation_et, event_json) =>
-    @get_message_from_db conversation_et, event_json.data.message_id
-    .then (message_to_delete_et) =>
-      if event_json.from isnt message_to_delete_et.from
-        throw new Error 'Sender can only delete own messages'
-      if event_json.from isnt @user_repository.self().id
-        return @_add_delete_message conversation_et.id, event_json.id, event_json.time, message_to_delete_et
-    .then =>
-      return @_delete_message conversation_et, event_json.data.message_id
-    .catch (error) =>
-      @logger.log "Failed to delete message for conversation '#{conversation_et.id}'", error
-      throw error
+    @logger.log "»» Event: '#{event.type}'", {event_object: event, event_json: JSON.stringify event}
+
+    # Ignore member join if we join a one2one conversation (accept a connection request)
+    if event.type is z.event.Backend.CONVERSATION.MEMBER_JOIN
+      connection_et = @user_repository.get_connection_by_conversation_id event.conversation
+      return if connection_et?.status() is z.user.ConnectionStatus.PENDING
+
+    # Check if conversation was archived
+    @get_conversation_by_id event.conversation, (conversation_et) =>
+      previously_archived = conversation_et.is_archived()
+
+      switch event.type
+        when z.event.Backend.CONVERSATION.CREATE
+          @_on_create event
+        when z.event.Backend.CONVERSATION.MEMBER_JOIN
+          @_on_member_join conversation_et, event
+        when z.event.Backend.CONVERSATION.MEMBER_LEAVE
+          @_on_member_leave conversation_et, event
+        when z.event.Backend.CONVERSATION.MEMBER_UPDATE
+          @_on_member_update conversation_et, event
+        when z.event.Backend.CONVERSATION.RENAME
+          @_on_rename conversation_et, event
+        when z.event.Backend.CONVERSATION.MESSAGE_ADD
+          @_on_message_add conversation_et, event
+        when z.event.Client.CONVERSATION.ASSET_UPLOAD_COMPLETE
+          @_on_asset_upload_complete conversation_et, event
+        when z.event.Client.CONVERSATION.ASSET_UPLOAD_FAILED
+          @_on_asset_upload_failed conversation_et, event
+        when z.event.Client.CONVERSATION.ASSET_PREVIEW
+          @_on_asset_preview conversation_et, event
+        when z.event.Client.CONVERSATION.MESSAGE_DELETE
+          @_on_message_deleted conversation_et, event
+        when z.event.Client.CONVERSATION.MESSAGE_HIDDEN
+          @_on_message_hidden event
+        when z.event.Client.CONVERSATION.REACTION
+          @_on_reaction conversation_et, event
+        else
+          @_on_add_event conversation_et, event
+
+      # Un-archive it also on the backend side
+      if not @block_event_handling and previously_archived and not conversation_et.is_archived()
+        @logger.log @logger.levels.INFO, "Unarchiving conversation '#{conversation_et.id}' with new event"
+        @unarchive_conversation conversation_et
 
   ###
   A message or ping received in a conversation.
+  @private
   @param conversation_et [z.entity.Conversation] Conversation to add the event to
   @param event_json [Object] JSON data of 'conversation.message-add' or 'conversation.knock' event
   ###
-  add_event: (conversation_et, event_json) =>
+  _on_add_event: (conversation_et, event_json) ->
     @_add_event_to_conversation event_json, conversation_et, (message_et) =>
-      @_send_event_notification event_json, conversation_et, message_et
+      @send_confirmation_status conversation_et, message_et
+      @_send_event_notification conversation_et, message_et
 
   ###
-  An asset was uploaded
-  @param event_json [Object] JSON data of 'conversation.asset-upload-complete' event
+  An asset preview was send.
+  @private
+  @param event_json [Object] JSON data of 'conversation.asset-upload-failed' event
   @return [z.entity.Conversation] The conversation that was created
   ###
-  asset_upload_complete: (conversation_et, event_json) ->
+  _on_asset_preview: (conversation_et, event_json) ->
     message_et = conversation_et.get_message_by_id event_json.id
 
     if not message_et?
-      return @logger.log @logger.levels.ERROR, "Upload complete: Could not find message with id '#{event_json.id}'", event_json
+      return @logger.log @logger.levels.ERROR, "Asset preview: Could not find message with id '#{event_json.id}'", event_json
 
-    @update_message_as_upload_complete conversation_et, message_et, event_json.data
+    @update_message_with_asset_preview conversation_et, message_et, event_json.data
 
   ###
-  An asset failed
-  @param event_json [Object] JSON data of 'conversation.asset-upload-failed' event
+  An asset was uploaded.
+  @private
+  @param event_json [Object] JSON data of 'conversation.asset-upload-complete' event
   @return [z.entity.Conversation] The conversation that was created
   ###
-  asset_upload_failed: (conversation_et, event_json) ->
+  _on_asset_upload_complete: (conversation_et, event_json) ->
     message_et = conversation_et.get_message_by_id event_json.id
 
     if not message_et?
-      return @logger.log @logger.levels.ERROR, "Upload failed: Could not find message with id '#{event_json.id}'", event_json
+      return @logger.log @logger.levels.ERROR, "Upload complete: Could not find message with id '#{event_json.id}'", event_json
 
-    if event_json.data.reason is z.assets.AssetUploadFailedReason.CANCELLED
-      @_delete_message conversation_et, message_et.id
-    else
-      @update_message_as_upload_failed message_et
+    @update_message_as_upload_complete conversation_et, message_et, event_json.data
 
   ###
-  An asset preview was send
+  An asset failed.
+  @private
   @param event_json [Object] JSON data of 'conversation.asset-upload-failed' event
   @return [z.entity.Conversation] The conversation that was created
   ###
-  asset_preview: (conversation_et, event_json) ->
+  _on_asset_upload_failed: (conversation_et, event_json) ->
     message_et = conversation_et.get_message_by_id event_json.id
 
     if not message_et?
-      return @logger.log @logger.levels.ERROR, 'Asset preview: Could not find message with id '#{event_json.id}'", event_json
+      return @logger.log @logger.levels.ERROR, "Upload failed: Could not find message with id '#{event_json.id}'", event_json
 
-    @update_message_with_asset_preview conversation_et, message_et, event_json.data
+    if event_json.data.reason is z.assets.AssetUploadFailedReason.CANCELLED
+      @_delete_message_by_id conversation_et, message_et.id
+    else
+      @update_message_as_upload_failed message_et
 
   ###
   A conversation was created.
+  @private
   @param event_json [Object] JSON data of 'conversation.create' event
   @return [z.entity.Conversation] The conversation that was created
   ###
-  create: (event_json) =>
+  _on_create: (event_json) ->
     conversation_et = @find_conversation_by_id event_json.id
 
     if not conversation_et?
@@ -1495,10 +1526,11 @@ class z.conversation.ConversationRepository
 
   ###
   User were added to a group conversation.
+  @private
   @param conversation_et [z.entity.Conversation] Conversation to add users to
   @param event_json [Object] JSON data of 'conversation.member-join' event
   ###
-  member_join: (conversation_et, event_json) =>
+  _on_member_join: (conversation_et, event_json) ->
     for user_id in event_json.data.user_ids when user_id isnt @user_repository.self().id
       conversation_et.participating_user_ids.push user_id if user_id not in conversation_et.participating_user_ids()
 
@@ -1512,10 +1544,11 @@ class z.conversation.ConversationRepository
 
   ###
   Members of a group conversation were removed or left.
+  @private
   @param conversation_et [z.entity.Conversation] Conversation to remove users from
   @param event_json [Object] JSON data of 'conversation.member-leave' event
   ###
-  member_leave: (conversation_et, event_json) =>
+  _on_member_leave: (conversation_et, event_json) ->
     @_add_event_to_conversation event_json, conversation_et, (message_et) =>
       for user_et in message_et.user_ets()
         if conversation_et.call()
@@ -1536,11 +1569,12 @@ class z.conversation.ConversationRepository
   ###
   Membership properties for a conversation were updated.
 
+  @private
   @param conversation_et [z.entity.Conversation] Conversation entity that will be updated
   @param event_json [Object] JSON data of 'conversation.member-update' event
   @param conversation_et [z.entity.Conversation] Next conversation in list
   ###
-  member_update: (conversation_et, event_json, next_conversation_et) =>
+  _on_member_update: (conversation_et, event_json, next_conversation_et) ->
     previously_archived = conversation_et.is_archived()
     next_conversation_et = @get_next_conversation conversation_et if not next_conversation_et?
 
@@ -1551,12 +1585,88 @@ class z.conversation.ConversationRepository
     else if conversation_et.is_archived()
       amplify.publish z.event.WebApp.CONVERSATION.SWITCH, conversation_et, next_conversation_et
 
+  ###
+  A text message received in a conversation.
+  @private
+  @param conversation_et [z.entity.Conversation] Conversation to add the event to
+  @param event_json [Object] JSON data of 'conversation.message-add'
+  ###
+  _on_message_add: (conversation_et, event_json) ->
+    Promise.resolve()
+    .then =>
+      if event_json.data.previews.length
+        return @_update_link_preview conversation_et, event_json
+      else if event_json.data.replacing_message_id
+        return @_update_edited_message conversation_et, event_json
+      return event_json
+    .then (updated_event_json) =>
+      @_on_add_event conversation_et, updated_event_json
+    .catch (error) ->
+      throw error if error.type isnt z.conversation.ConversationError::TYPE.MESSAGE_NOT_FOUND
+
+  ###
+  A hide message received in a conversation.
+  @private
+  @param conversation_et [z.entity.Conversation] Conversation to add the event to
+  @param event_json [Object] JSON data of 'conversation.message-delete'
+  ###
+  _on_message_deleted: (conversation_et, event_json) =>
+    @get_message_in_conversation_by_id conversation_et, event_json.data.message_id
+    .then (message_to_delete_et) =>
+      if event_json.from isnt message_to_delete_et.from
+        throw new z.conversation.ConversationError z.conversation.ConversationError::TYPE.WRONG_USER
+      if event_json.from isnt @user_repository.self().id
+        return @_add_delete_message conversation_et.id, event_json.id, event_json.time, message_to_delete_et
+    .then =>
+      return @_delete_message_by_id conversation_et, event_json.data.message_id
+    .catch (error) =>
+      if error.type isnt z.conversation.ConversationError::TYPE.MESSAGE_NOT_FOUND
+        @logger.log "Failed to delete message for conversation '#{conversation_et.id}'", error
+        throw error
+
+  ###
+  A hide message received in a conversation.
+  @private
+  @param event_json [Object] JSON data of 'conversation.message-hidden'
+  ###
+  _on_message_hidden: (event_json) =>
+    Promise.resolve()
+    .then =>
+      if event_json.from isnt @user_repository.self().id
+        throw new Error 'Sender is not self user'
+      return @find_conversation_by_id event_json.data.conversation_id
+    .then (conversation_et) =>
+      return @_delete_message_by_id conversation_et, event_json.data.message_id
+    .catch (error) =>
+      @logger.log "Failed to delete message for conversation '#{conversation_et.id}'", error
+      throw error
+
+  ###
+  Someone reacted to a message.
+  @private
+  @param conversation_et [z.entity.Conversation] Conversation entity that a message was reacted upon in
+  @param event_json [Object] JSON data of 'conversation.reaction' event
+  ###
+  _on_reaction: (conversation_et, event_json) ->
+    @get_message_in_conversation_by_id conversation_et, event_json.data.message_id
+    .then (message_et) =>
+      message_et.update_reactions event_json
+      @_update_user_ets message_et
+      @_send_reaction_notification conversation_et, message_et, event_json
+      @logger.log @logger.levels.DEBUG, "Reaction to message '#{event_json.data.message_id}' in conversation '#{conversation_et.id}'", event_json
+      return @conversation_service.update_message_in_db message_et, {reactions: message_et.reactions()}
+    .catch (error) =>
+      if error.type isnt z.conversation.ConversationError::TYPE.MESSAGE_NOT_FOUND
+        @logger.log "Failed to handle reaction to message in conversation '#{conversation_et.id}'", error
+        throw error
+
   ###
   A conversation was renamed.
+  @private
   @param conversation_et [z.entity.Conversation] Conversation entity that will be renamed
   @param event_json [Object] JSON data of 'conversation.rename' event
   ###
-  rename: (conversation_et, event_json) =>
+  _on_rename: (conversation_et, event_json) ->
     @_add_event_to_conversation event_json, conversation_et, (message_et) =>
       @conversation_mapper.update_properties conversation_et, event_json.data
       amplify.publish z.event.WebApp.SYSTEM_NOTIFICATION.NOTIFY, conversation_et, message_et
@@ -1670,68 +1780,29 @@ class z.conversation.ConversationRepository
   Forward the event to the SystemNotification repository for browser and audio notifications.
 
   @private
-  @param event_json [Object] JSON data of received event
-  @param conversation_et [z.entity.Conversation] Conversation that was created
+  @param conversation_et [z.entity.Conversation] Conversation that event was received in
   @param message_et [z.entity.Message] Message that has been received
   ###
-  _send_event_notification: (event_json, conversation_et, message_et) ->
+  _send_event_notification: (conversation_et, message_et) ->
     amplify.publish z.event.WebApp.SYSTEM_NOTIFICATION.NOTIFY, conversation_et, message_et
 
   ###
-  Listener for incoming events from the WebSocket.
+  Forward the reaction event to the SystemNotification repository for browser and audio notifications.
 
   @private
-  @note We check for events received multiple times via the WebSocket by event id here
-  @param event [Object] JSON data for event
-  ####
-  on_conversation_event: (event) =>
-    if not event
-      error = new Error('Event response is undefined')
-      custom_data =
-        source: 'WebSocket'
-      Raygun.send error, custom_data
-
-    @logger.log "»» Event: '#{event.type}'", {event_object: event, event_json: JSON.stringify event}
-
-    # Ignore member join if we join a one2one conversation (accept a connection request)
-    if event.type is z.event.Backend.CONVERSATION.MEMBER_JOIN
-      connection_et = @user_repository.get_connection_by_conversation_id event.conversation
-      return if connection_et?.status() is z.user.ConnectionStatus.PENDING
-
-    # Check if conversation was archived
-    @get_conversation_by_id event.conversation, (conversation_et) =>
-      previously_archived = conversation_et.is_archived()
-
-      switch event.type
-        when z.event.Backend.CONVERSATION.CREATE
-          @create event
-        when z.event.Backend.CONVERSATION.MEMBER_JOIN
-          @member_join conversation_et, event
-        when z.event.Backend.CONVERSATION.MEMBER_LEAVE
-          @member_leave conversation_et, event
-        when z.event.Backend.CONVERSATION.MEMBER_UPDATE
-          @member_update conversation_et, event
-        when z.event.Backend.CONVERSATION.RENAME
-          @rename conversation_et, event
-        when z.event.Backend.CONVERSATION.ASSET_UPLOAD_COMPLETE
-          @asset_upload_complete conversation_et, event
-        when z.event.Backend.CONVERSATION.ASSET_UPLOAD_FAILED
-          @asset_upload_failed conversation_et, event
-        when z.event.Backend.CONVERSATION.ASSET_PREVIEW
-          @asset_preview conversation_et, event
-        when z.event.Backend.CONVERSATION.MESSAGE_ADD
-          @message_added conversation_et, event
-        when z.event.Backend.CONVERSATION.MESSAGE_DELETE
-          @message_deleted conversation_et, event
-        when z.event.Backend.CONVERSATION.MESSAGE_HIDDEN
-          @message_hidden event
-        else
-          @add_event conversation_et, event
+  @param conversation_et [z.entity.Conversation] Conversation that event was received in
+  @param message_et [z.entity.Message] Message that has been reacted upon
+  @param event_json [Object] JSON data of received reaction event
+  ###
+  _send_reaction_notification: (conversation_et, message_et, event_json) ->
+    return if not event_json.data.reaction
+    return if message_et.from isnt @user_repository.self().id
 
-      # Un-archive it also on the backend side
-      if not @is_handling_notifications and previously_archived and not conversation_et.is_archived()
-        @logger.log @logger.levels.INFO, "Unarchiving conversation '#{conversation_et.id}' with new event"
-        @unarchive_conversation conversation_et
+    @user_repository.get_user_by_id event_json.from, (user_et) ->
+      reaction_message_et = new z.entity.Message message_et.id, z.message.SuperType.REACTION
+      reaction_message_et.user user_et
+      reaction_message_et.reaction = event_json.data.reaction
+      amplify.publish z.event.WebApp.SYSTEM_NOTIFICATION.NOTIFY, conversation_et, reaction_message_et
 
   ###
   Updates the user entities that are part of a message.
@@ -1741,16 +1812,27 @@ class z.conversation.ConversationRepository
   _update_user_ets: (message_et, callback) =>
     @user_repository.get_user_by_id message_et.from, (user_et) =>
       message_et.user user_et
+
       if message_et.is_member()
         @user_repository.get_users_by_id message_et.user_ids(), (user_ets) ->
           message_et.user_ets user_ets
-      else if message_et.has_asset_text()
+
+      if message_et.reactions
+        if Object.keys(message_et.reactions()).length
+          user_ids = (user_id for user_id of message_et.reactions())
+          @user_repository.get_users_by_id user_ids, (user_ets) ->
+            message_et.reactions_user_ets user_ets
+        else
+          message_et.reactions_user_ets.removeAll()
+
+      if message_et.has_asset_text()
         for asset_et in message_et.assets() when asset_et.is_text()
           if not message_et.user()
             Raygun.send new Error 'Message does not contain user when updating'
           else
             asset_et.theme_color = message_et.user().accent_color()
-      callback? message_et
+
+      return callback? message_et
 
   ###
   Cancel asset upload.
@@ -1759,7 +1841,7 @@ class z.conversation.ConversationRepository
   cancel_asset_upload: (message_et) =>
     conversation_et = @active_conversation()
     @asset_service.cancel_asset_upload message_et.assets()[0].upload_id()
-    @_delete_message conversation_et, message_et.id
+    @_delete_message_by_id conversation_et, message_et.id
     @send_asset_upload_failed conversation_et, message_et.id, z.assets.AssetUploadFailedReason.CANCELLED
 
   _handle_deleted_clients: (deleted_client_map, payload) ->
@@ -1815,11 +1897,20 @@ class z.conversation.ConversationRepository
         throw error_response
 
   ###
-  Delete message from UI an database
+  Delete message from UI and database. Primary key is used to delete message in database.
+  @param conversation_et [z.entity.Conversation] Conversation that contains the message
+  @param message_et [z.entity.Message] Message to delete
+  ###
+  _delete_message: (conversation_et, message_et) =>
+    conversation_et.remove_message_by_id message_et.id
+    @conversation_service.delete_message_with_key_from_db conversation_et.id, message_et.primary_key
+
+  ###
+  Delete message from UI and database
   @param conversation_et [z.entity.Conversation] Conversation that contains the message
   @param message_id [String] Message to delete
   ###
-  _delete_message: (conversation_et, message_id) =>
+  _delete_message_by_id: (conversation_et, message_id) =>
     conversation_et.remove_message_by_id message_id
     @conversation_service.delete_message_from_db conversation_et.id, message_id
 
@@ -1891,21 +1982,40 @@ class z.conversation.ConversationRepository
     asset_et.preview_resource resource
     @conversation_service.update_asset_preview_in_db message_et.primary_key, asset_data
 
-
   ###
-  Update edited message with timestamp from the original message
-  @return [Object] updated event_json
+  Update edited message with timestamp from the original message and delete original
+  @param conversation_et [z.entity.Conversation] Conversation of edited message
+  @param event_json [JSON] Edit message event
+  @return [Object] Updated event_json
   ###
   _update_edited_message: (conversation_et, event_json) =>
-    @get_message_from_db conversation_et, event_json.data.replacing_message_id
+    @get_message_in_conversation_by_id conversation_et, event_json.data.replacing_message_id
     .then (original_message_et) =>
       if event_json.from isnt original_message_et.from
-        throw new Error 'Sender can only edit own messages'
-      return [original_message_et, @event_mapper.map_json_event event_json, conversation_et]
-    .then ([original_message_et, edited_message_et]) =>
-      return @conversation_service.update_message_timestamp_in_db edited_message_et.primary_key, original_message_et.timestamp
-    .then (record) ->
-      return record.mapped
+        throw new z.conversation.ConversationError z.conversation.ConversationError::TYPE.WRONG_USER
+      if not original_message_et.timestamp
+        throw new TypeError 'Missing timestamp'
+
+      event_json.time = new Date(original_message_et.timestamp).toISOString()
+
+      return @conversation_service.update_message_in_db event_json, {time: event_json.time}
+    .then =>
+      @_delete_message_by_id conversation_et, event_json.data.replacing_message_id
+      return event_json
+
+  ###
+  Update link preview message
+  @param conversation_et [z.entity.Conversation] Conversation of edited message
+  @param event_json [JSON] Edit message event
+  @return [Object] Updated event_json
+  ###
+  _update_link_preview: (conversation_et, event_json) =>
+    @get_message_in_conversation_by_id conversation_et, event_json.id
+    .then (original_message_et) =>
+      @_delete_message conversation_et, original_message_et
+    .then ->
+      return event_json
+
 
   ###############################################################################
   # Helpers
diff --git a/app/script/conversation/ConversationService.coffee b/app/script/conversation/ConversationService.coffee
index 87630c593f5..2821904dfea 100644
--- a/app/script/conversation/ConversationService.coffee
+++ b/app/script/conversation/ConversationService.coffee
@@ -195,53 +195,50 @@ class z.conversation.ConversationService
       callback: callback
 
   ###
-  Delete events from a conversation.
+  Delete a message from a conversation with the given primary.
 
-  @param message_id [String] ID of conversation to remove message from
-  @param primary_key [String] ID of the actual message
+  @param conversation_id [String] ID of conversation to remove message from
+  @param message_id [String] ID of the actual message
+  @return [Promise] Resolves with the number of deleted records
+  ###
+  delete_message_with_key_from_db: (conversation_id, primary_key) ->
+    @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS].delete primary_key
+
+  ###
+  Delete a message from a conversation. Duplicates are delete as well.
+
+  @param conversation_id [String] ID of conversation to remove message from
+  @param message_id [String] ID of the actual message
   @return [Promise] Resolves with the number of deleted records
   ###
   delete_message_from_db: (conversation_id, message_id) ->
     @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS]
-    .where 'raw.conversation'
+    .where 'conversation'
     .equals conversation_id
-    .and (record) -> record.mapped?.id is message_id
+    .and (record) -> record.id is message_id
     .delete()
 
   ###
-  Delete events from a conversation.
-
-  @param conversation_id [String] delete message for this conversation
+  Delete all message of a conversation.
+  @param conversation_id [String] Delete messages for this conversation
   ###
   delete_messages_from_db: (conversation_id) ->
     @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS]
-    .where 'raw.conversation'
+    .where 'conversation'
     .equals conversation_id
     .delete()
 
   ###
-  Update events timestamp.
-
-  @param primary_key [String] Primary key used to find an event in the database
-  @param timestamp [Number]
-  ###
-  update_message_timestamp_in_db: (primary_key, timestamp) ->
-    updated_record = undefined
-    Promise.resolve()
-    .then ->
-      if not timestamp?
-        throw new TypeError 'Missing timestamp'
-    .then =>
-      @storage_service.load @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key
-    .then (record) =>
-      record.mapped.data.edited_time = record.mapped.time
-      record.mapped.time = record.raw.time = new Date(timestamp).toISOString()
-      record.meta.timestamp = timestamp
-      updated_record = record
-      @storage_service.update @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key, record
-    .then =>
-      @logger.log 'Updated message_et timestamp', primary_key
-      return updated_record
+  Update events reactions.
+  @param message_et [z.entity.Message] Message event to update in the database
+  @param changes [Object] Changes to update message with
+  ###
+  update_message_in_db: (message_et, changes) ->
+    Promise.resolve message_et.primary_key or z.storage.StorageService.construct_primary_key message_et
+    .then (primary_key) =>
+      if _.isObject(changes) and changes[Object.keys(changes)[0]]?
+        return @storage_service.update @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key, changes
+      throw new z.conversation.ConversationError z.conversation.ConversationError::TYPE.NO_CHANGES
 
   ###
   Delete events from a conversation.
@@ -251,10 +248,10 @@ class z.conversation.ConversationService
   update_asset_as_uploaded_in_db: (primary_key, asset_data) ->
     @storage_service.load @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key
     .then (record) =>
-      record.mapped.data.id = asset_data.id
-      record.mapped.data.otr_key = asset_data.otr_key
-      record.mapped.data.sha256 = asset_data.sha256
-      record.mapped.data.status = z.assets.AssetTransferState.UPLOADED
+      record.data.id = asset_data.id
+      record.data.otr_key = asset_data.otr_key
+      record.data.sha256 = asset_data.sha256
+      record.data.status = z.assets.AssetTransferState.UPLOADED
       @storage_service.update @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key, record
     .then =>
       @logger.log 'Updated asset message_et (uploaded)', primary_key
@@ -267,9 +264,9 @@ class z.conversation.ConversationService
   update_asset_preview_in_db: (primary_key, asset_data) ->
     @storage_service.load @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key
     .then (record) =>
-      record.mapped.data.preview_id = asset_data.id
-      record.mapped.data.preview_otr_key = asset_data.otr_key
-      record.mapped.data.preview_sha256 = asset_data.sha256
+      record.data.preview_id = asset_data.id
+      record.data.preview_otr_key = asset_data.otr_key
+      record.data.preview_sha256 = asset_data.sha256
       @storage_service.update @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key, record
     .then =>
       @logger.log 'Updated asset message_et (preview)', primary_key
@@ -282,15 +279,15 @@ class z.conversation.ConversationService
   update_asset_as_failed_in_db: (primary_key, reason) ->
     @storage_service.load @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key
     .then (record) =>
-      record.mapped.data.status = z.assets.AssetTransferState.UPLOAD_FAILED
-      record.mapped.data.reason = reason
+      record.data.status = z.assets.AssetTransferState.UPLOAD_FAILED
+      record.data.reason = reason
       @storage_service.update @storage_service.OBJECT_STORE_CONVERSATION_EVENTS, primary_key, record
     .then =>
       @logger.log 'Updated asset message_et (failed)', primary_key
 
   ###
   Loads conversation states from the local database.
-
+  @return [Promise] Promise that resolves with all the stored conversation states
   ###
   load_conversation_states_from_db: =>
     return new Promise (resolve, reject) =>
@@ -311,9 +308,9 @@ class z.conversation.ConversationService
   load_event_from_db: (conversation_id, message_id) ->
     return new Promise (resolve, reject) =>
       @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS]
-      .where 'raw.conversation'
+      .where 'conversation'
       .equals conversation_id
-      .filter (record) -> record.mapped?.id is message_id
+      .filter (record) -> record.id is message_id
       .first()
       .then (record) ->
         resolve record
@@ -323,52 +320,33 @@ class z.conversation.ConversationService
         reject error
 
   ###
-  Load conversation events.
+  Load conversation events. Start and end are not included.
+  Events are always sorted beginning with the newest timestamp.
 
   @param conversation_id [String] ID of conversation
-  @param offset [String] Timestamp that loaded events have to undercut
+  @param start [Number] starting from this timestamp
+  @param end [Number] stop when reaching timestamp
   @param limit [Number] Amount of events to load
-  @return [Promise] Promise that resolves with the retrieved records ([events, has_further_events])
-  ###
-  load_events_from_db: (conversation_id, offset, limit = z.config.MESSAGES_FETCH_LIMIT) ->
-    return new Promise (resolve, reject) =>
-      @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS]
-      .where 'raw.conversation'
-      .equals conversation_id
-      .reverse()
-      .sortBy 'meta.timestamp'
-      .then (records) ->
-        records = (record for record in records when record.meta.timestamp < offset) if offset
-        has_further_events = records.length > limit
-        resolve [records.slice(0, limit), has_further_events]
-      .catch (error) =>
-        @logger.log @logger.levels.ERROR,
-          "Failed to get events for conversation '#{conversation_id}': #{error.message}", error
-        reject error
-
-  ###
-  Load all unread events of a conversation.
-
-  @param conversation_et [z.entity.Conversation] Conversation entity
-  @param offset [String] Timestamp that loaded events have to undercut
   @return [Promise] Promise that resolves with the retrieved records
   ###
-  load_unread_events_from_db: (conversation_et, offset) ->
-    return new Promise (resolve, reject) =>
-      conversation_id = conversation_et.id
-      @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS]
-      .where 'raw.conversation'
-      .equals conversation_id
-      .reverse()
-      .sortBy 'raw.time'
-      .then (records) ->
-        records = (record for record in records when record.meta.timestamp < offset) if offset
-        records = (record for record in records when record.meta.timestamp > conversation_et.last_read_timestamp())
-        resolve records
-      .catch (error) =>
-        @logger.log @logger.levels.ERROR,
-          "Failed to get unread events for conversation '#{conversation_et.id}': #{error.message}", error
-        reject error
+  load_events_from_db: (conversation_id, start, end, limit) ->
+    @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS]
+    .where 'conversation'
+    .equals conversation_id
+    .reverse()
+    .sortBy 'time'
+    .then (records) ->
+      return records.filter (record) ->
+        timestamp = new Date(record.time).getTime()
+        return false if start and timestamp >= start
+        return false if end and timestamp <= end
+        return true
+    .then (records) ->
+      return records.slice 0, limit
+    .catch (error) =>
+      @logger.log @logger.levels.ERROR,
+        "Failed to get events for conversation '#{conversation_id}': #{error.message}", error
+      throw error
 
   ###
   Add users to an existing conversation.
@@ -397,16 +375,20 @@ class z.conversation.ConversationService
     }
   }
 
-  @param conversation_id [String] ID of conversation to send message in
+  @note Options for the precondition check on missing clients are:
+    'false' - all clients, 'Array<String>' - only clients of listed users, 'true' - force sending  @param conversation_id [String] ID of conversation to send message in
   @param payload [Object] Payload to be posted
   @option [OtrRecipients] recipients Map with per-recipient data
   @option [String] sender Client ID of the sender
-  @param force_sending [Boolean] Should the backend ignore missing clients
+  @param precondition_option [Array<String>|Boolean] Level that backend checks for missing clients
   @return [Promise] Promise that resolve when the message was sent
   ###
-  post_encrypted_message: (conversation_id, payload, force_sending) ->
+  post_encrypted_message: (conversation_id, payload, precondition_option) ->
     url = @client.create_url "/conversations/#{conversation_id}/otr/messages"
-    url = "#{url}?ignore_missing=true" if force_sending
+    if _.isArray precondition_option
+      url = "#{url}?report_missing=#{precondition_option.join ','}"
+    else if precondition_option
+      url = "#{url}?ignore_missing=true"
 
     @client.send_json
       url: url
diff --git a/app/script/conversation/EventMapper.coffee b/app/script/conversation/EventMapper.coffee
index 5cc3dda5af5..b13eeba0dc4 100644
--- a/app/script/conversation/EventMapper.coffee
+++ b/app/script/conversation/EventMapper.coffee
@@ -45,7 +45,7 @@ class z.conversation.EventMapper
     try
       return @_map_json_event event, conversation_et
     catch error
-      @logger.log @logger.levels.ERROR, 'Cannot map event', {error: error, event: event}
+      @logger.log @logger.levels.ERROR, "Failed to map event: #{error.message}", {error: error, event: event}
       return undefined
 
   ###
@@ -58,10 +58,10 @@ class z.conversation.EventMapper
   ###
   _map_json_event: (event, conversation_et) ->
     switch event.type
-      when z.event.Backend.CONVERSATION.ASSET_META
-        message_et = @_map_event_asset_meta event
       when z.event.Backend.CONVERSATION.ASSET_ADD
         message_et = @_map_event_asset_add event
+      when z.event.Backend.CONVERSATION.KNOCK
+        message_et = @_map_event_ping event
       when z.event.Backend.CONVERSATION.MESSAGE_ADD
         message_et = @_map_event_message_add event
       when z.event.Backend.CONVERSATION.MEMBER_JOIN
@@ -69,29 +69,32 @@ class z.conversation.EventMapper
       when z.event.Backend.CONVERSATION.MEMBER_LEAVE
         message_et = @_map_event_member_leave event
       when z.event.Backend.CONVERSATION.MEMBER_UPDATE
-        message_et = @_map_event_member_update()
+        message_et = @_map_event_member_update event
       when z.event.Backend.CONVERSATION.RENAME
         message_et = @_map_event_rename event
       when z.event.Backend.CONVERSATION.VOICE_CHANNEL_ACTIVATE
         message_et = @_map_event_voice_channel_activate()
       when z.event.Backend.CONVERSATION.VOICE_CHANNEL_DEACTIVATE
         message_et = @_map_event_voice_channel_deactivate event
-      when z.event.Backend.CONVERSATION.KNOCK
-        message_et = @_map_event_ping event
-      when z.event.Backend.CONVERSATION.LOCATION
+      when z.event.Client.CONVERSATION.ASSET_META
+        message_et = @_map_event_asset_meta event
+      when z.event.Client.CONVERSATION.DELETE_EVERYWHERE
+        message_et = @_map_system_event_delete_everywhere event
+      when z.event.Client.CONVERSATION.LOCATION
         message_et = @_map_event_location event
       when z.event.Client.CONVERSATION.UNABLE_TO_DECRYPT
         message_et = @_map_system_event_unable_to_decrypt event
-      when z.event.Client.CONVERSATION.DELETE_EVERYWHERE
-        message_et = @_map_system_event_delete_everywhere event
       else
         message_et = @_map_event_ignored()
 
     message_et.id = event.id
-    message_et.type = event.type
     message_et.from = event.from
     message_et.timestamp = new Date(event.time).getTime()
-    message_et.primary_key = "#{conversation_et.id}@#{message_et.from}@#{message_et.timestamp}"
+    message_et.primary_key = z.storage.StorageService.construct_primary_key event
+    message_et.type = event.type
+
+    if message_et.is_reactable()
+      message_et.reactions event.reactions or {}
 
     if window.isNaN message_et.timestamp
       @logger.log @logger.levels.WARN, "Could not get timestamp for message '#{message_et.id}'. Skipping it.", event
@@ -211,8 +214,10 @@ class z.conversation.EventMapper
 
   @return [z.entity.MemberMessage] Member message entity
   ###
-  _map_event_member_update: ->
+  _map_event_member_update: (event) ->
     message_et = new z.entity.MemberMessage()
+    # don't render last read
+    message_et.visible not event.data.last_read_timestamp
     return message_et
 
   ###
diff --git a/app/script/cryptography/CryptographyError.coffee b/app/script/cryptography/CryptographyError.coffee
index ce4b43abed1..cfe524920c9 100644
--- a/app/script/cryptography/CryptographyError.coffee
+++ b/app/script/cryptography/CryptographyError.coffee
@@ -20,11 +20,30 @@ window.z ?= {}
 z.cryptography ?= {}
 
 class z.cryptography.CryptographyError
-  constructor: (message, type) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message
     @stack = (new Error()).stack
-    @type = type
+    @type = type or z.cryptography.CryptographyError::UNKNOWN
+
+    @message = switch @type
+      when z.cryptography.CryptographyError::TYPE.BROKEN_EXTERNAL
+        'Failed to map external message'
+      when z.cryptography.CryptographyError::TYPE.IGNORED_ASSET
+        'Ignored asset preview'
+      when z.cryptography.CryptographyError::TYPE.IGNORED_HOT_KNOCK
+        'Ignored hot knock'
+      when z.cryptography.CryptographyError::TYPE.IGNORED_PREVIEW
+        'Ignored image preview'
+      when z.cryptography.CryptographyError::TYPE.NO_DATA_CONTENT
+        'No message data content found'
+      when z.cryptography.CryptographyError::TYPE.NO_GENERIC_MESSAGE
+        'No GenericMessage found'
+      when z.cryptography.CryptographyError::TYPE.PREVIOUSLY_STORED
+        'Message was previously stored'
+      when z.cryptography.CryptographyError::TYPE.UNHANDLED_TYPE
+        'Unhandled event type'
+      else
+        'Unknown CryptographyError'
 
   @:: = new Error()
   @::constructor = @
@@ -33,6 +52,8 @@ class z.cryptography.CryptographyError
     IGNORED_ASSET: 'z.cryptography.CryptographyError::TYPE.IGNORED_ASSET'
     IGNORED_HOT_KNOCK: 'z.cryptography.CryptographyError::TYPE.IGNORED_HOT_KNOCK'
     IGNORED_PREVIEW: 'z.cryptography.CryptographyError::TYPE.IGNORED_PREVIEW'
-    MISSING_MESSAGE: 'z.cryptography.CryptographyError::TYPE.MISSING_MESSAGE'
+    NO_DATA_CONTENT: 'z.cryptography.CryptographyError::TYPE.NO_DATA_CONTENT'
+    NO_GENERIC_MESSAGE: 'z.cryptography.CryptographyError::TYPE.NO_GENERIC_MESSAGE'
     PREVIOUSLY_STORED: 'z.cryptography.CryptographyError::TYPE.PREVIOUSLY_STORED'
     UNHANDLED_TYPE: 'z.cryptography.CryptographyError::TYPE.UNHANDLED_TYPE'
+    UNKNOWN: 'z.cryptography.CryptographyError::TYPE.UNKNOWN'
diff --git a/app/script/cryptography/CryptographyMapper.coffee b/app/script/cryptography/CryptographyMapper.coffee
index d2cf9e6e893..9eca0f862d9 100644
--- a/app/script/cryptography/CryptographyMapper.coffee
+++ b/app/script/cryptography/CryptographyMapper.coffee
@@ -32,39 +32,33 @@ class z.cryptography.CryptographyMapper
   @return [Object] Promise that resolves with the mapped event
   ###
   map_generic_message: (generic_message, event) =>
-    mapped = undefined
-
     Promise.resolve()
-    .then ->
+    .then =>
       if not generic_message
-        error_message = "Failed to map OTR event '#{event.id}' as decrypted generic message is missing"
-        throw new z.cryptography.CryptographyError error_message, z.cryptography.CryptographyError::TYPE.MISSING_MESSAGE
-    .then ->
-      mapped =
+        throw new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.NO_GENERIC_MESSAGE
+      return @_map_generic_message generic_message, event
+    .then (specific_content) ->
+      return $.extend
         conversation: event.conversation
         id: generic_message.message_id
         from: event.from
         time: event.time
-    .then =>
-      return @_map_generic_message generic_message, event
-    .then (specific_content) ->
-      $.extend mapped, specific_content
-      return mapped
+      , specific_content
 
-  _map_generic_message: (generic_message, event) ->
+  _map_generic_message: (generic_message, event) =>
     switch generic_message.content
       when 'asset'
         return @_map_asset generic_message.asset, generic_message.message_id, event.data?.id
       when 'cleared'
         return @_map_cleared generic_message.cleared
-      when 'hidden'
-        return @_map_hidden generic_message.hidden
       when 'deleted'
         return @_map_deleted generic_message.deleted
       when 'edited'
         return @_map_edited generic_message.edited, generic_message.message_id
       when 'external'
         return @_map_external generic_message.external, event
+      when 'hidden'
+        return @_map_hidden generic_message.hidden
       when 'image'
         return @_map_image generic_message.image, event.data.id
       when 'knock'
@@ -73,11 +67,13 @@ class z.cryptography.CryptographyMapper
         return @_map_last_read generic_message.lastRead
       when 'location'
         return @_map_location generic_message.location, generic_message.message_id
+      when 'reaction'
+        return @_map_reaction generic_message.reaction
       when 'text'
         return @_map_text generic_message.text, generic_message.message_id
       else
-        error_message = "Skipped event '#{generic_message.message_id}' of unhandled type '#{generic_message.content}'"
-        throw new z.cryptography.CryptographyError error_message, z.cryptography.CryptographyError::TYPE.UNHANDLED_TYPE
+        @logger.log @logger.levels.WARN, "Skipped event '#{generic_message.message_id}' of unhandled type '#{generic_message.content}'"
+        throw new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.UNHANDLED_TYPE
 
   _map_asset: (asset, event_nonce, event_id) ->
     if asset.uploaded?
@@ -89,9 +85,9 @@ class z.cryptography.CryptographyMapper
     else if asset.original?
       return @_map_asset_original asset.original, event_nonce
     else
-      error_message = 'Ignored asset preview'
-      @logger.log @logger.levels.INFO, error_message
-      throw new z.cryptography.CryptographyError error_message, z.cryptography.CryptographyError::TYPE.IGNORED_ASSET
+      error = new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.IGNORED_ASSET
+      @logger.log @logger.levels.INFO, error.message
+      throw error
 
   _map_asset_meta_data: (original) ->
     if original.audio?
@@ -100,6 +96,13 @@ class z.cryptography.CryptographyMapper
         loudness: new Uint8Array(original.audio.normalized_loudness?.toArrayBuffer() or [])
       }
 
+  _map_asset_not_uploaded: (not_uploaded) ->
+    return {
+      data:
+        reason: not_uploaded
+      type: z.event.Client.CONVERSATION.ASSET_UPLOAD_FAILED
+    }
+
   _map_asset_original: (original, event_nonce) ->
     return {
       data:
@@ -109,14 +112,16 @@ class z.cryptography.CryptographyMapper
           name: original.name
           nonce: event_nonce
         meta: @_map_asset_meta_data(original)
-      type: z.event.Backend.CONVERSATION.ASSET_META
+      type: z.event.Client.CONVERSATION.ASSET_META
     }
 
-  _map_asset_not_uploaded: (not_uploaded) ->
+  _map_asset_preview: (preview, event_id) ->
     return {
       data:
-        reason: not_uploaded
-      type: z.event.Backend.CONVERSATION.ASSET_UPLOAD_FAILED
+        id: event_id
+        otr_key: new Uint8Array preview.remote.otr_key?.toArrayBuffer()
+        sha256: new Uint8Array preview.remote.sha256?.toArrayBuffer()
+      type: z.event.Client.CONVERSATION.ASSET_PREVIEW
     }
 
   _map_asset_uploaded: (uploaded, event_id) ->
@@ -125,16 +130,7 @@ class z.cryptography.CryptographyMapper
         id: event_id
         otr_key: new Uint8Array uploaded.otr_key?.toArrayBuffer()
         sha256: new Uint8Array uploaded.sha256?.toArrayBuffer()
-      type: z.event.Backend.CONVERSATION.ASSET_UPLOAD_COMPLETE
-    }
-
-  _map_asset_preview: (preview, event_id) ->
-    return {
-      data:
-        id: event_id
-        otr_key: new Uint8Array preview.remote.otr_key?.toArrayBuffer()
-        sha256: new Uint8Array preview.remote.sha256?.toArrayBuffer()
-      type: z.event.Backend.CONVERSATION.ASSET_PREVIEW
+      type: z.event.Client.CONVERSATION.ASSET_UPLOAD_COMPLETE
     }
 
   _map_cleared: (cleared) ->
@@ -145,21 +141,18 @@ class z.cryptography.CryptographyMapper
       type: z.event.Backend.CONVERSATION.MEMBER_UPDATE
     }
 
-  _map_hidden: (hidden) ->
-    return {
-      data:
-        conversation_id: hidden.conversation_id
-        message_id: hidden.message_id
-      type: z.event.Backend.CONVERSATION.MESSAGE_HIDDEN
-    }
-
   _map_deleted: (deleted) ->
     return {
       data:
         message_id: deleted.message_id
-      type: z.event.Backend.CONVERSATION.MESSAGE_DELETE
+      type: z.event.Client.CONVERSATION.MESSAGE_DELETE
     }
 
+  _map_edited: (edited, event_id) ->
+    mapped = @_map_text edited.text, event_id
+    mapped.data.replacing_message_id = edited.replacing_message_id
+    return mapped
+
   ###
   Unpacks a specific generic message which is wrapped inside an external generic message.
 
@@ -180,15 +173,24 @@ class z.cryptography.CryptographyMapper
       @logger.log @logger.levels.INFO, "Received external message of type '#{generic_message.content}'", generic_message
       return @_map_generic_message generic_message, event
     .catch (error) ->
-      throw new z.cryptography.CryptographyError error.message, z.cryptography.CryptographyError::TYPE.BROKEN_EXTERNAL
+      @logger.log @logger.levels.ERROR, "Failed to map external message: #{error.message}", error
+      throw new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.BROKEN_EXTERNAL
+
+  _map_hidden: (hidden) ->
+    return {
+      data:
+        conversation_id: hidden.conversation_id
+        message_id: hidden.message_id
+      type: z.event.Client.CONVERSATION.MESSAGE_HIDDEN
+    }
 
   _map_image: (image, event_id) ->
     if image.tag is 'medium'
       return @_map_image_medium image, event_id
     else
-      error_message = 'Ignored image preview'
-      @logger.log @logger.levels.INFO, error_message
-      throw new z.cryptography.CryptographyError error_message, z.cryptography.CryptographyError::TYPE.IGNORED_PREVIEW
+      error = new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.IGNORED_PREVIEW
+      @logger.log @logger.levels.INFO, error.message
+      throw error
 
   _map_image_medium: (image, event_id) ->
     return {
@@ -211,9 +213,9 @@ class z.cryptography.CryptographyMapper
 
   _map_knock: (knock, event_id) ->
     if knock.hot_knock
-      error_message = 'Ignored hot knock'
-      @logger.log @logger.levels.INFO, error_message
-      throw new z.cryptography.CryptographyError error_message, z.cryptography.CryptographyError::TYPE.IGNORED_HOT_KNOCK
+      error = new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.IGNORED_HOT_KNOCK
+      @logger.log @logger.levels.INFO, error.message
+      throw error
     else
       return {
         data:
@@ -238,7 +240,15 @@ class z.cryptography.CryptographyMapper
           name: location.name
           zoom: location.zoom
         nonce: event_id
-      type: z.event.Backend.CONVERSATION.LOCATION
+      type: z.event.Client.CONVERSATION.LOCATION
+    }
+
+  _map_reaction: (reaction) ->
+    return {
+      data:
+        message_id: reaction.message_id
+        reaction: reaction.emoji
+      type: z.event.Client.CONVERSATION.REACTION
     }
 
   _map_text: (text, event_id) ->
@@ -249,8 +259,3 @@ class z.cryptography.CryptographyMapper
         previews: text.link_preview.map (preview) -> preview.encode64()
       type: z.event.Backend.CONVERSATION.MESSAGE_ADD
     }
-
-  _map_edited: (edited, event_id) ->
-    mapped = @_map_text edited.text, event_id
-    mapped.data.replacing_message_id = edited.replacing_message_id
-    return mapped
diff --git a/app/script/cryptography/CryptographyRepository.coffee b/app/script/cryptography/CryptographyRepository.coffee
index 2863d164ba5..28985f8b054 100644
--- a/app/script/cryptography/CryptographyRepository.coffee
+++ b/app/script/cryptography/CryptographyRepository.coffee
@@ -97,10 +97,10 @@ class z.cryptography.CryptographyRepository
       return response.prekey
     .catch (error) ->
       if error.code is z.service.BackendClientError::STATUS_CODE.NOT_FOUND
-        throw new z.user.UserError 'Pre-key not found', z.user.UserError::TYPE.PRE_KEY_NOT_FOUND
+        throw new z.user.UserError z.user.UserError::TYPE.PRE_KEY_NOT_FOUND
       else
-        error_message = "Failed to get pre-key from backend: #{error.message}"
-        throw new z.user.UserError error_message, z.user.UserError::TYPE.REQUEST_FAILURE
+        @logger.log @logger.levels.ERROR, "Failed to get pre-key from backend: #{error.message}"
+        throw new z.user.UserError z.user.UserError::TYPE.REQUEST_FAILURE
 
   ###
   Get a pre-key for client of in the user client map.
@@ -112,8 +112,8 @@ class z.cryptography.CryptographyRepository
     .then (response) ->
       return response
     .catch (error) ->
-      error_message = "Failed to get pre-key from backend: #{error.message}"
-      throw new z.user.UserError error_message, z.user.UserError::TYPE.REQUEST_FAILURE
+      @logger.log @logger.levels.ERROR, "Failed to get pre-key from backend: #{error.message}"
+      throw new z.user.UserError z.user.UserError::TYPE.REQUEST_FAILURE
 
   ###
   Construct the pre-key.
@@ -471,9 +471,8 @@ class z.cryptography.CryptographyRepository
   decrypt_event: (event) =>
     return new Promise (resolve, reject) =>
       if not event.data
-        error_message = new Error "Encrypted event with ID '#{event.id}' does not contain its data payload"
-        @logger.log @logger.levels.ERROR, error_message, event
-        reject new z.cryptography.CryptographyError error_message, z.cryptography.CryptographyError::TYPE.MISSING_MESSAGE
+        @logger.log @logger.levels.ERROR, "Encrypted event with ID '#{event.id}' does not contain its data payload", event
+        reject new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.NO_DATA_CONTENT
         return
 
       if event.type is z.event.Backend.CONVERSATION.OTR_ASSET_ADD
@@ -481,15 +480,14 @@ class z.cryptography.CryptographyRepository
       else if event.type is z.event.Backend.CONVERSATION.OTR_MESSAGE_ADD
         ciphertext = event.data.text
 
-      primary_key = @storage_repository.construct_primary_key event.conversation, event.from, event.time
+      primary_key = z.storage.StorageService.construct_primary_key event
       @storage_repository.load_event_for_conversation primary_key
       .then (loaded_event) =>
         if loaded_event is undefined
           resolve @_decrypt_message event, ciphertext
         else
-          error_message = "Skipped decryption of event '#{event.type}' (#{primary_key}) because it was previously stored"
-          @logger.log @logger.levels.INFO, error_message
-          reject new z.cryptography.CryptographyError error_message, z.cryptography.CryptographyError::TYPE.PREVIOUSLY_STORED
+          @logger.log @logger.levels.INFO, "Skipped decryption of event '#{event.type}' (#{primary_key}) because it was previously stored"
+          reject new z.cryptography.CryptographyError z.cryptography.CryptographyError::TYPE.PREVIOUSLY_STORED
       .catch (decrypt_error) =>
         # Get error information
         receiving_client_id = event.data.recipient
@@ -560,16 +558,12 @@ class z.cryptography.CryptographyRepository
   save_encrypted_event: (generic_message, event) =>
     @cryptography_mapper.map_generic_message generic_message, event
     .then (mapped) =>
-      primary_key = @storage_repository.construct_primary_key event.conversation, event.from, event.time
-      return @storage_repository.save_decrypted_conversation_event primary_key, event, mapped
-    .then (primary_key) =>
-      @logger.log @logger.levels.INFO, "Saved '#{generic_message.content}' (OTR) with primary key '#{primary_key}'"
-      return @storage_repository.load_event_for_conversation primary_key
+      return @storage_repository.save_conversation_event mapped
     .catch (error) =>
-      @logger.log @logger.levels.ERROR, "Saving encrypted message failed: #{error.message}", error
       if error instanceof z.cryptography.CryptographyError
         return undefined
       else
+        @logger.log @logger.levels.ERROR, "Saving encrypted message failed: #{error.message}", error
         throw error
 
   ###
@@ -578,10 +572,7 @@ class z.cryptography.CryptographyRepository
   @return [Promise] Promise that will resolve with the saved record
   ###
   save_unencrypted_event: (event) ->
-    @storage_repository.save_unencrypted_conversation_event event
-    .then (primary_key) =>
-      @logger.log @logger.levels.INFO, "Saved unencrypted event '#{event.type}' with primary key '#{primary_key}'"
-      @storage_repository.load_event_for_conversation primary_key
+    @storage_repository.save_conversation_event event
     .catch (error) =>
       @logger.log @logger.levels.ERROR, "Saving unencrypted message failed: #{error.message}", error
       throw error
diff --git a/app/script/entity/Conversation.coffee b/app/script/entity/Conversation.coffee
index dc8d061c511..202d278e481 100644
--- a/app/script/entity/Conversation.coffee
+++ b/app/script/entity/Conversation.coffee
@@ -323,7 +323,7 @@ class z.entity.Conversation
     if message_et.has_nonce() and other_message_et.has_nonce() and message_et.nonce is other_message_et.nonce
       sorted_messages = z.entity.Message.sort_by_timestamp [message_et, other_message_et]
       amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.SessionEventName.INTEGER.EVENT_HIDDEN_DUE_TO_DUPLICATE_NONCE
-      if message_et.type is z.event.Backend.CONVERSATION.ASSET_META and other_message_et.type is z.event.Backend.CONVERSATION.ASSET_META
+      if message_et.type is z.event.Client.CONVERSATION.ASSET_META and other_message_et.type is z.event.Client.CONVERSATION.ASSET_META
         # android sends to meta messages with the same content. we would store both and but only update the first one
         # whenever we reload the conversation the nonce check would hide the older one and we would show the non updated message
         # to fix that we hide the newer one
@@ -475,8 +475,7 @@ class z.entity.Conversation
   @return [z.entity.Message, undefined] Message with ID or undefined
   ###
   get_message_by_id: (id) ->
-    for message_et in @messages()
-      return message_et if message_et.id is id
+    return message_et for message_et in @messages() when message_et.id is id
 
   ###
   Returns a message with an image if found by correlation ID and image type.
diff --git a/app/script/entity/message/ContentMessage.coffee b/app/script/entity/message/ContentMessage.coffee
index 5d5180303b2..462651f6374 100644
--- a/app/script/entity/message/ContentMessage.coffee
+++ b/app/script/entity/message/ContentMessage.coffee
@@ -31,12 +31,41 @@ class z.entity.ContentMessage extends z.entity.Message
     @replacing_message_id = null
     @edited_timestamp = null
 
+    @reactions = ko.observable {}
+    @reactions_user_ets = ko.observableArray()
+    @reactions_user_ids = ko.pureComputed => (@reactions_user_ets().map (user_et) -> user_et.first_name()).join ', '
+
     @display_edited_timestamp = =>
       return  z.localization.Localizer.get_text {
         id: z.string.conversation_edit_timestamp
         replace: {placeholder: '%@timestamp', content: moment(@edited_timestamp).format 'HH:mm'}
       }
 
+    # like
+    @is_liked_provisional = ko.observable()
+    @is_liked = ko.pureComputed
+      read: =>
+        if @is_liked_provisional()?
+          is_liked_provisional = @is_liked_provisional()
+          @is_liked_provisional null
+          return is_liked_provisional
+        likes = @reactions_user_ets().filter (user_et) -> return user_et.is_me
+        return likes.length is 1
+      write: (value) =>
+        @is_liked_provisional value
+    @other_likes = ko.pureComputed =>
+      return @reactions_user_ets().filter (user_et) -> return not user_et.is_me
+    @show_likes = ko.observable false
+
+    @like_caption = ko.pureComputed =>
+      if @reactions_user_ets().length <= 5
+        return (@reactions_user_ets().map (user_et) -> user_et.first_name()).join ', '
+      else
+        return  z.localization.Localizer.get_text {
+          id: z.string.conversation_likes_caption
+          replace: {placeholder: '%@number', content: @reactions_user_ets().length}
+        }
+
   ###
   Add another content asset to the message.
 
@@ -53,6 +82,14 @@ class z.entity.ContentMessage extends z.entity.Message
   get_first_asset: ->
     return @assets()[0]
 
+  update_reactions: (event_json) ->
+    reactions = @reactions()
+    if event_json.data.reaction
+      reactions[event_json.from] = event_json.data.reaction
+    else
+      delete reactions[event_json.from]
+    @reactions reactions
+
   ###
   Check whether the message was edited.
 
diff --git a/app/script/entity/message/Message.coffee b/app/script/entity/message/Message.coffee
index 364b19fff4c..c2e2abf2f51 100644
--- a/app/script/entity/message/Message.coffee
+++ b/app/script/entity/message/Message.coffee
@@ -21,12 +21,19 @@ z.entity ?= {}
 
 # Base message entity.
 class z.entity.Message
+  ###
+  Sort messages by timestamp
+  @return [Boolean] Is message of type system
+  ###
+  @sort_by_timestamp: (message_ets) ->
+    message_ets.sort (m1, m2) -> m1.timestamp > m2.timestamp
+
   # Construct a new base message entity.
-  constructor: ->
+  constructor: (id = '0', super_type = '') ->
     @from = ''
-    @id = '0'
+    @id = id
     @primary_key = undefined
-    @super_type = ''
+    @super_type = super_type
     @timestamp = Date.now()
     @type = ''
     @user = ko.observable new z.entity.User()
@@ -47,7 +54,6 @@ class z.entity.Message
 
   ###
   Check if message contains a preview image asset.
-
   @return [Boolean] Message contains a preview image
   ###
   has_asset: ->
@@ -57,7 +63,6 @@ class z.entity.Message
 
   ###
   Check if message contains any image asset.
-
   @return [Boolean] Message contains any image
   ###
   has_asset_image: ->
@@ -67,7 +72,6 @@ class z.entity.Message
 
   ###
   Check if message contains a medium image asset.
-
   @return [Boolean] Message contains a medium image
   ###
   has_asset_medium_image: ->
@@ -77,7 +81,6 @@ class z.entity.Message
 
   ###
   Check if message contains a preview image asset.
-
   @return [Boolean] Message contains a preview image
   ###
   has_asset_preview_image: ->
@@ -87,7 +90,6 @@ class z.entity.Message
 
   ###
   Check if message contains a preview image asset.
-
   @return [Boolean] Message contains a preview image
   ###
   has_asset_file: ->
@@ -97,7 +99,6 @@ class z.entity.Message
 
   ###
   Check if message contains a text asset.
-
   @return [Boolean] Message contains text
   ###
   has_asset_text: ->
@@ -107,7 +108,6 @@ class z.entity.Message
 
   ###
   Check if message contains a nonce.
-
   @return [Boolean] Message contains a nonce
   ###
   has_nonce: ->
@@ -115,7 +115,6 @@ class z.entity.Message
 
   ###
   Check if message is a call message.
-
   @return [Boolean] Is message of type call
   ###
   is_call: ->
@@ -123,7 +122,6 @@ class z.entity.Message
 
   ###
   Check if message is a content message.
-
   @return [Boolean] Is message of type content
   ###
   is_content: ->
@@ -131,7 +129,6 @@ class z.entity.Message
 
   ###
   Check if message is a member message.
-
   @return [Boolean] Is message of type member
   ###
   is_member: ->
@@ -139,7 +136,6 @@ class z.entity.Message
 
   ###
   Check if message is a ping message.
-
   @return [Boolean] Is message of type ping
   ###
   is_ping: ->
@@ -147,7 +143,6 @@ class z.entity.Message
 
   ###
   Check if message is a system message.
-
   @return [Boolean] Is message of type system
   ###
   is_system: ->
@@ -155,7 +150,6 @@ class z.entity.Message
 
   ###
   Check if message is a e2ee message.
-
   @return [Boolean] Is message of type system
   ###
   is_device: ->
@@ -163,7 +157,6 @@ class z.entity.Message
 
   ###
   Check if message is a e2ee message.
-
   @return [Boolean] Is message of type system
   ###
   is_all_verified: ->
@@ -171,7 +164,6 @@ class z.entity.Message
 
   ###
   Check if message is a e2ee message.
-
   @return [Boolean] Is message of type system
   ###
   is_unable_to_decrypt: ->
@@ -179,7 +171,6 @@ class z.entity.Message
 
   ###
   Check if message can be deleted.
-
   @return [Boolean]
   ###
   is_deletable: ->
@@ -188,38 +179,14 @@ class z.entity.Message
 
   ###
   Check if message can be edited.
-
   @return [Boolean]
   ###
   is_editable: ->
     return @has_asset_text() and @user().is_me
 
   ###
-  Triggers event to delete message.
-  ###
-  edit: =>
-    amplify.publish z.event.WebApp.CONVERSATION.MESSAGE.EDIT, @
-
-  ###
-  Triggers event to delete message.
-  ###
-  delete: =>
-    active_conversation = wire.app.repository.conversation.active_conversation()
-    amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.DELETE_MESSAGE,
-      action: => amplify.publish z.event.WebApp.CONVERSATION.MESSAGE.DELETE_SELF, active_conversation, @
-
-  ###
-  Triggers event to delete message for everyone.
-  ###
-  delete_everyone: =>
-    active_conversation = wire.app.repository.conversation.active_conversation()
-    amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.DELETE_EVERYONE_MESSAGE,
-      action: => amplify.publish z.event.WebApp.CONVERSATION.MESSAGE.DELETE_EVERYONE, active_conversation, @
-
-  ###
-  Sort messages by timestamp
-
-  @return [Boolean] Is message of type system
+  Check if message can be reacted to.
+  @return [Boolean]
   ###
-  @sort_by_timestamp: (message_ets) ->
-    message_ets.sort (m1, m2) -> m1.timestamp > m2.timestamp
+  is_reactable: ->
+    return @is_content()
diff --git a/app/script/event/Backend.coffee b/app/script/event/Backend.coffee
index 821c108e32e..45b6830b228 100644
--- a/app/script/event/Backend.coffee
+++ b/app/script/event/Backend.coffee
@@ -24,30 +24,22 @@ Enum of different backend events.
 ###
 z.event.Backend =
   CALL:
-    STATE: 'call.state'
+    FLOW_ACTIVE: 'call.flow-active'
     FLOW_ADD: 'call.flow-add'
+    FLOW_DELETE: 'call.flow-delete'
     REMOTE_SDP: 'call.remote-sdp'
     REMOTE_CANDIDATES_ADD: 'call.remote-candidates-add'
     REMOTE_CANDIDATES_UPDATE: 'call.remote-candidates-update'
-    FLOW_ACTIVE: 'call.flow-active'
-    FLOW_DELETE: 'call.flow-delete'
+    STATE: 'call.state'
   CONVERSATION:
     ASSET_ADD: 'conversation.asset-add'
-    ASSET_META: 'conversation.asset-meta'
-    ASSET_PREVIEW: 'conversation.asset-preview'
-    ASSET_UPLOAD_COMPLETE: 'conversation.asset-upload-complete'
-    ASSET_UPLOAD_FAILED: 'conversation.asset-upload-failed'
-    CLIENT_MESSAGE_ADD: 'conversation.client-message-add'
     CONNECT_REQUEST: 'conversation.connect-request'
     CREATE: 'conversation.create'
     KNOCK: 'conversation.knock'
-    LOCATION: 'conversation.location'
     MEMBER_JOIN: 'conversation.member-join'
     MEMBER_LEAVE: 'conversation.member-leave'
     MEMBER_UPDATE: 'conversation.member-update'
     MESSAGE_ADD: 'conversation.message-add'
-    MESSAGE_HIDDEN: 'conversation.message-hidden'
-    MESSAGE_DELETE: 'conversation.message-delete'
     OTR_ASSET_ADD: 'conversation.otr-asset-add'
     OTR_MESSAGE_ADD: 'conversation.otr-message-add'
     RENAME: 'conversation.rename'
@@ -56,9 +48,8 @@ z.event.Backend =
     VOICE_CHANNEL_DEACTIVATE: 'conversation.voice-channel-deactivate'
   USER:
     ACTIVATE: 'user.activate'
+    CLIENT_ADD: 'user.client-add'
+    CLIENT_REMOVE: 'user.client-remove'
     CONNECTION: 'user.connection'
-    UPDATE: 'user.update'
     DELETE: 'user.delete'
-    CLIENT:
-      ADD: 'user.client-add'
-      REMOVE: 'user.client-remove'
+    UPDATE: 'user.update'
diff --git a/app/script/event/Client.coffee b/app/script/event/Client.coffee
index 8f4c0fd3ff2..b5c8d4fd049 100644
--- a/app/script/event/Client.coffee
+++ b/app/script/event/Client.coffee
@@ -21,5 +21,13 @@ z.event ?= {}
 
 z.event.Client =
   CONVERSATION:
-    UNABLE_TO_DECRYPT: 'conversation.unable-to-decrypt'
+    ASSET_META: 'conversation.asset-meta'
+    ASSET_PREVIEW: 'conversation.asset-preview'
+    ASSET_UPLOAD_COMPLETE: 'conversation.asset-upload-complete'
+    ASSET_UPLOAD_FAILED: 'conversation.asset-upload-failed'
     DELETE_EVERYWHERE: 'conversation.delete-everywhere'
+    LOCATION: 'conversation.location'
+    MESSAGE_DELETE: 'conversation.message-delete'
+    MESSAGE_HIDDEN: 'conversation.message-hidden'
+    REACTION: 'conversation.reaction'
+    UNABLE_TO_DECRYPT: 'conversation.unable-to-decrypt'
diff --git a/app/script/event/EventError.coffee b/app/script/event/EventError.coffee
index dd1826b8383..15c26c25d66 100644
--- a/app/script/event/EventError.coffee
+++ b/app/script/event/EventError.coffee
@@ -20,19 +20,33 @@ window.z ?= {}
 z.event ?= {}
 
 class z.event.EventError
-  constructor: (message, type) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message
+    @type = type or z.event.EventError::TYPE.UNKNOWN
     @stack = (new Error()).stack
-    @type = type
+
+    @message = switch @type
+      when z.event.EventError::TYPE.DATABASE_FAILURE
+        'Event related database transaction failure'
+      when z.event.EventError::TYPE.DEPRECATED_SCHEMA
+        'Event type is deprecated'
+      when z.event.EventError::TYPE.NO_CLIENT_ID
+        'Missing client id'
+      when z.event.EventError::TYPE.NO_LAST_ID
+        'Last notification ID not found in storage'
+      when z.event.EventError::TYPE.NO_NOTIFICATIONS
+        'No notifications found'
+      when z.event.EventError::TYPE.REQUEST_FAILURE
+        'Event related backend request failure'
+      else
+        'Unknown EventError'
 
   @:: = new Error()
   @::constructor = @
   @::TYPE =
     DATABASE_FAILURE: 'z.event.EventError::TYPE.DATABASE_FAILURE'
-    DATABASE_NOT_FOUND: 'z.event.EventError::TYPE.DATABASE_NOT_FOUND'
-    LAST_ID_NOT_SPECIFIED: 'z.event.EventError::TYPE.LAST_ID_NOT_SPECIFIED'
-    MISSING_CLIENT_ID: 'z.event.EventError::TYPE.MISSING_CLIENT_ID'
+    DEPRECATED_SCHEMA: 'z.event.EventError::TYPE.DEPRECATED_SCHEMA'
+    NO_CLIENT_ID: 'z.event.EventError::TYPE.NO_CLIENT_ID'
+    NO_LAST_ID: 'z.event.EventError::TYPE.NO_LAST_ID'
     NO_NOTIFICATIONS: 'z.event.EventError::TYPE.NO_NOTIFICATIONS'
     REQUEST_FAILURE: 'z.event.EventError::TYPE.REQUEST_FAILURE'
-    OUTDATED_SCHEMA: 'Outdated event schema'
diff --git a/app/script/event/EventRepository.coffee b/app/script/event/EventRepository.coffee
index 99eaf00d1d3..be124da9e7d 100644
--- a/app/script/event/EventRepository.coffee
+++ b/app/script/event/EventRepository.coffee
@@ -23,8 +23,8 @@ z.event ?= {}
 class z.event.EventRepository
   @::NOTIFICATION_SOURCE =
     INJECTION: 'Injection'
-    SOCKET: 'WebSocket'
     STREAM: 'Notification Stream'
+    WEB_SOCKET: 'WebSocket'
 
 
   ###
@@ -39,6 +39,19 @@ class z.event.EventRepository
 
     @current_client = undefined
 
+    @notification_handling_state = ko.observable z.event.NotificationHandlingState.STREAM
+    @notification_handling_state.subscribe (handling_state) =>
+      @logger.log @logger.levels.OFF, "Changed notification handling state to '#{handling_state}'"
+      amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, handling_state
+
+      if handling_state is z.event.NotificationHandlingState.WEB_SOCKET
+        @_handle_buffered_notifications()
+        if @previous_handling_state is z.event.NotificationHandlingState.RECOVERY
+          amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.CONNECTIVITY_RECOVERY
+      @previous_handling_state = handling_state
+
+    @previous_handling_state = @notification_handling_state()
+
     @notifications_handled = 0
     @notifications_loaded = ko.observable false
     @notifications_promises = []
@@ -47,7 +60,7 @@ class z.event.EventRepository
     @notifications_blocked = false
 
     @notifications_queue.subscribe (notifications) =>
-      if notifications.length > 0
+      if notifications.length
         return if @notifications_blocked
 
         notification = @notifications_queue()[0]
@@ -64,39 +77,20 @@ class z.event.EventRepository
             replace = [@notifications_handled, @notifications_total]
             amplify.publish z.event.WebApp.APP.UPDATE_INIT, z.string.init_events_progress, false, replace
 
-      else if @notifications_loaded() and not @can_handle_web_socket()
+      else if @notifications_loaded() and not @notification_handling_state() isnt z.event.NotificationHandlingState.WEB_SOCKET
         @logger.log @logger.levels.INFO, "Done handling '#{@notifications_total}' notifications from the stream"
-        if @is_recovering()
-          @is_recovering false
-        else
-          amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, false
+        @notification_handling_state z.event.NotificationHandlingState.WEB_SOCKET
         @find_ongoing_calls()
-        @can_handle_web_socket true
         @notifications_loaded false
         @notifications_promises[0] @last_notification_id()
 
     @web_socket_buffer = []
-    @can_handle_web_socket = ko.observable false
-    @can_handle_web_socket.subscribe (was_handled) =>
-      @_handle_buffered_notifications() if was_handled
 
     @last_notification_id = ko.observable undefined
     @last_notification_id.subscribe (last_notification_id) =>
       @logger.log @logger.levels.INFO, "Last notification ID updated to '#{last_notification_id}'"
       @notification_service.save_last_notification_id_to_db last_notification_id if last_notification_id
 
-    @is_recovering = ko.observable false
-    @is_recovering.subscribe (is_recovering) =>
-      if is_recovering
-        amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, true
-        @can_handle_web_socket false
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECOVERY
-      else
-        amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, false
-        @can_handle_web_socket true
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.CONNECTIVITY_RECOVERY
-
-    amplify.subscribe z.event.WebApp.CONNECTION.RECONNECT, @reconnect
     amplify.subscribe z.event.WebApp.CONNECTION.ONLINE, @recover_from_notification_stream
     amplify.subscribe z.event.WebApp.EVENT.INJECT, @inject_event
 
@@ -106,13 +100,13 @@ class z.event.EventRepository
   ###############################################################################
 
   # Initiate the WebSocket connection.
-  connect: =>
+  connect_web_socket: =>
     if not @current_client().id
-      throw new z.event.EventError 'Missing client id', z.event.EventError::TYPE.MISSING_CLIENT_ID
+      throw new z.event.EventError z.event.EventError::TYPE.NO_CLIENT_ID
 
     @web_socket_service.client_id = @current_client().id
     @web_socket_service.connect (notification) =>
-      if @can_handle_web_socket()
+      if @notification_handling_state() is z.event.NotificationHandlingState.WEB_SOCKET
         @notifications_queue.push notification
       else
         @_buffer_web_socket_notification notification
@@ -121,15 +115,15 @@ class z.event.EventRepository
   Close the WebSocket connection.
   @param trigger [z.event.WebSocketService::CHANGE_TRIGGER] Trigger of the disconnect
   ###
-  disconnect: (trigger) =>
+  disconnect_web_socket: (trigger) =>
     @web_socket_service.reset trigger
 
   ###
   Re-connect the WebSocket connection.
-  @param trigger [z.event.WebSocketService::CHANGE_TRIGGER] Trigger of the disconnect
+  @param trigger [z.event.WebSocketService::CHANGE_TRIGGER] Trigger of the reconnect
   ###
-  reconnect: (trigger) =>
-    @can_handle_web_socket false
+  reconnect_web_socket: (trigger) =>
+    @notification_handling_state z.event.NotificationHandlingState.RECOVERY
     @web_socket_service.reconnect trigger
 
   ###
@@ -142,8 +136,9 @@ class z.event.EventRepository
   # Handle buffered notifications.
   _handle_buffered_notifications: =>
     @logger.log @logger.levels.INFO, "Received '#{@web_socket_buffer.length}' notifications via WebSocket while recovering from stream"
-    z.util.ko_array_push_all @notifications_queue, @web_socket_buffer
-    @web_socket_buffer.length = 0
+    if @web_socket_buffer.length
+      z.util.ko_array_push_all @notifications_queue, @web_socket_buffer
+      @web_socket_buffer.length = 0
 
 
   ###############################################################################
@@ -178,9 +173,8 @@ class z.event.EventRepository
             amplify.publish z.event.WebApp.APP.UPDATE_INIT, z.string.init_events_expectation, true, [@notifications_total]
 
         else
-          error_message = "No notifications found since '#{last_notification_id}'"
-          @logger.log @logger.levels.INFO, error_message, response
-          reject new z.event.EventError error_message, z.event.EventError::TYPE.NO_NOTIFICATIONS
+          @logger.log @logger.levels.INFO, "No notifications found since '#{last_notification_id}'", response
+          reject new z.event.EventError z.event.EventError::TYPE.NO_NOTIFICATIONS
 
       @notification_service.get_notifications @current_client().id, last_notification_id, limit
       .then (response) -> _got_notifications response
@@ -190,13 +184,11 @@ class z.event.EventRepository
         if response.notifications
           _got_notifications response
         else if error.code is z.service.BackendClientError::STATUS_CODE.NOT_FOUND
-          error_message = "No notifications found since '#{last_notification_id}'"
-          @logger.log @logger.levels.INFO, error_message, response
-          reject new z.event.EventError error_message, z.event.EventError::TYPE.NO_NOTIFICATIONS
+          @logger.log @logger.levels.INFO, "No notifications found since '#{last_notification_id}'", response
+          reject new z.event.EventError z.event.EventError::TYPE.NO_NOTIFICATIONS
         else
-          error_message = "Failed to get notifications: #{error.message}"
-          @logger.log @logger.levels.ERROR, error_message, error
-          reject new z.event.EventError error_message, z.event.EventError::TYPE.REQUEST_FAILURE
+          @logger.log @logger.levels.ERROR, "Failed to get notifications: #{error.message}", error
+          reject new z.event.EventError z.event.EventError::TYPE.REQUEST_FAILURE
 
   ###
   Get the last notification ID for a given client.
@@ -213,17 +205,18 @@ class z.event.EventRepository
   Will retrieve missed notifications from the stream after a connectivity loss.
   ###
   recover_from_notification_stream: =>
-    @is_recovering true
+    @notification_handling_state z.event.NotificationHandlingState.RECOVERY
+    amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECOVERY
     @update_from_notification_stream()
     .then (number_of_notifications) =>
-      @is_recovering false if number_of_notifications is 0
+      @notification_handling_state z.event.NotificationHandlingState.WEB_SOCKET if number_of_notifications is 0
       @logger.log @logger.levels.INFO, "Retrieved '#{number_of_notifications}' notifications from stream after connectivity loss"
     .catch (error) =>
       if error.type isnt z.event.EventError::TYPE.NO_NOTIFICATIONS
         @logger.log @logger.levels.ERROR, "Failed to recover from notification stream: #{error.message}", error
-        @is_recovering false
+        @notification_handling_state z.event.NotificationHandlingState.WEB_SOCKET
         # @todo What do we do in this case?
-        amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
+        amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
 
   ###
   Fetch all missed events from the notification stream since the last ID stored in database.
@@ -241,9 +234,8 @@ class z.event.EventRepository
           @logger.log @logger.levels.INFO, "ID of last notification fetched from stream is '#{last_notification_id}'"
         resolve @notifications_total
       .catch (error) =>
-        @can_handle_web_socket true
-        if error.type in [z.event.EventError::TYPE.NO_NOTIFICATIONS, z.event.EventError::TYPE.DATABASE_NOT_FOUND]
-          amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, false
+        @notification_handling_state z.event.NotificationHandlingState.WEB_SOCKET
+        if error.type in [z.event.EventError::TYPE.NO_LAST_ID, z.event.EventError::TYPE.NO_NOTIFICATIONS]
           @find_ongoing_calls()
           @logger.log @logger.levels.INFO, 'No notifications found for this user', error
           resolve 0
@@ -265,12 +257,10 @@ class z.event.EventRepository
   get_conversation_ids_with_active_events: (include_on, exclude_on) =>
     return new Promise (resolve, reject) =>
       @cryptography_repository.storage_repository.load_events_by_types _.flatten [include_on, exclude_on]
-      .then (records) ->
-        raw_events = (record.raw for record in records)
-
+      .then (events) ->
         filtered_conversations = {}
 
-        for event in raw_events
+        for event in events
           conversation_id = event.conversation
           if event.type in include_on
             filtered_conversations[conversation_id] = null
@@ -332,45 +322,29 @@ class z.event.EventRepository
   @param event [JSON] Backend event extracted from notification stream
   @return [Promise] Resolves with the saved record or boolean true if the event was skipped
   ###
-  _handle_event: (event, source) ->
-    return new Promise (resolve, reject) =>
-      sending_client = event.data?.sender
-      if sending_client
-        log_message = "Received encrypted event '#{event.type}' from client '#{sending_client}' of user '#{event.from}'"
-      else if event.from
-        log_message = "Received unencrypted event '#{event.id}' of type '#{event.type}' from user '#{event.from}'"
-        if event.type in [
-          z.event.Backend.CONVERSATION.ASSET_ADD
-          z.event.Backend.CONVERSATION.KNOCK
-          z.event.Backend.CONVERSATION.MESSAGE_ADD
-        ]
-          throw new z.event.EventError z.event.EventError::TYPE.OUTDATED_SCHEMA
-      else
-        log_message = "Received call event '#{event.type}' in conversation '#{event.conversation}'"
-      @logger.log @logger.levels.INFO, log_message, {event_object: event, event_json: JSON.stringify event}
-
-      if event.type in z.event.EventTypeHandling.IGNORE
-        @logger.log "Event ignored: '#{event.type}'", {event_object: event, event_json: JSON.stringify event}
-        return resolve true
-      else if event.type in z.event.EventTypeHandling.DECRYPT
-        promise = @cryptography_repository.decrypt_event(event).then (generic_message) =>
-          @cryptography_repository.save_encrypted_event generic_message, event
-      else if event.type in z.event.EventTypeHandling.STORE
-        promise = @cryptography_repository.save_unencrypted_event event
-      else
-        promise = Promise.resolve {raw: event}
-
-      promise.then (record) =>
-        if record and (source is @NOTIFICATION_SOURCE.SOCKET or @is_recovering or record.raw.type.startsWith 'conversation')
-          @_distribute_event record.mapped or record.raw
-        resolve record
-      .catch (error) =>
-        if error.type is z.cryptography.CryptographyError::TYPE.PREVIOUSLY_STORED
-          resolve true
-        else
-          @logger.log @logger.levels.ERROR,
-            "Failed to handle '#{event.type}' event '#{event.id or 'no ID'}' from '#{source}': '#{error.message}'", event
-          reject error
+  _handle_event: (event) ->
+    if event.type in z.event.EventTypeHandling.IGNORE
+      @logger.log "Event ignored: '#{event.type}'", {event_object: event, event_json: JSON.stringify event}
+      return Promise.resolve true
+
+    Promise.resolve()
+    .then =>
+      if event.type in z.event.EventTypeHandling.DECRYPT
+        return @cryptography_repository.decrypt_event(event)
+        .then (generic_message) =>
+          @cryptography_repository.cryptography_mapper.map_generic_message generic_message, event
+      return event
+    .then (mapped_event) =>
+      if mapped_event.type in z.event.EventTypeHandling.STORE
+        return @cryptography_repository.save_unencrypted_event mapped_event
+      return mapped_event
+    .then (saved_event) =>
+      @_distribute_event saved_event
+      return saved_event
+    .catch (error) ->
+      if error.type is z.cryptography.CryptographyError::TYPE.PREVIOUSLY_STORED
+        return true
+      throw error
 
   ###
   Handle all events from the payload of an incoming notification.
@@ -380,7 +354,11 @@ class z.event.EventRepository
   _handle_notification: (notification) =>
     return new Promise (resolve, reject) =>
       events = notification.payload
-      source = if @can_handle_web_socket() then @NOTIFICATION_SOURCE.SOCKET else @NOTIFICATION_SOURCE.STREAM
+      source = switch @notification_handling_state()
+        when z.event.NotificationHandlingState.WEB_SOCKET
+          @NOTIFICATION_SOURCE.WEB_SOCKET
+        else
+          @NOTIFICATION_SOURCE.STREAM
 
       @logger.log @logger.levels.INFO,
         "Handling notification '#{notification.id}' from '#{source}' containing '#{events.length}' events", notification
@@ -390,17 +368,10 @@ class z.event.EventRepository
         @last_notification_id notification.id
         resolve @last_notification_id()
       else
-        proceed = =>
+        Promise.all (@_handle_event event for event in events)
+        .then =>
           @last_notification_id notification.id
           resolve @last_notification_id()
-
-        Promise.all (@_handle_event event, source for event in events)
-        .then ->
-          proceed()
         .catch (error) =>
-          if error.message is z.event.EventError::TYPE.OUTDATED_SCHEMA
-            @logger.log @logger.levels.WARN, "Ignored notification '#{notification.id}' from '#{source}': #{error.message}", error
-            proceed()
-          else
-            @logger.log @logger.levels.ERROR, "Failed to handle notification '#{notification.id}' from '#{source}': #{error.message}", error
-            reject error
+          @logger.log @logger.levels.ERROR, "Failed to handle notification '#{notification.id}' from '#{source}': #{error.message}", error
+          reject error
diff --git a/app/script/event/EventTypeHandling.coffee b/app/script/event/EventTypeHandling.coffee
index 03af5c6a2dc..1cb19eab155 100644
--- a/app/script/event/EventTypeHandling.coffee
+++ b/app/script/event/EventTypeHandling.coffee
@@ -20,25 +20,34 @@ window.z ?= {}
 z.event ?= {}
 
 z.event.EventTypeHandling =
+  CONFIRM: [
+    z.event.Backend.CONVERSATION.ASSET_ADD
+    z.event.Backend.CONVERSATION.KNOCK
+    z.event.Backend.CONVERSATION.MESSAGE_ADD
+    z.event.Client.CONVERSATION.LOCATION
+    z.event.Client.CONVERSATION.REACTION
+  ]
   DECRYPT: [
     z.event.Backend.CONVERSATION.OTR_ASSET_ADD
     z.event.Backend.CONVERSATION.OTR_MESSAGE_ADD
   ]
   IGNORE: [
-    z.event.Backend.CONVERSATION.CLIENT_MESSAGE_ADD
+    z.event.Backend.CONVERSATION.ASSET_ADD
+    z.event.Backend.CONVERSATION.KNOCK
+    z.event.Backend.CONVERSATION.MESSAGE_ADD
     z.event.Backend.CONVERSATION.TYPING
   ]
   STORE: [
     z.event.Backend.CONVERSATION.ASSET_ADD
-    z.event.Backend.CONVERSATION.HOT_KNOCK
     z.event.Backend.CONVERSATION.KNOCK
-    z.event.Backend.CONVERSATION.LOCATION
     z.event.Backend.CONVERSATION.MEMBER_JOIN
     z.event.Backend.CONVERSATION.MEMBER_LEAVE
     z.event.Backend.CONVERSATION.MESSAGE_ADD
     z.event.Backend.CONVERSATION.RENAME
     z.event.Backend.CONVERSATION.VOICE_CHANNEL_ACTIVATE
     z.event.Backend.CONVERSATION.VOICE_CHANNEL_DEACTIVATE
-    z.event.Client.CONVERSATION.UNABLE_TO_DECRYPT
+    z.event.Client.CONVERSATION.ASSET_META
     z.event.Client.CONVERSATION.DELETE_EVERYWHERE
+    z.event.Client.CONVERSATION.LOCATION
+    z.event.Client.CONVERSATION.UNABLE_TO_DECRYPT
   ]
diff --git a/app/script/event/NotificationHandlingState.coffee b/app/script/event/NotificationHandlingState.coffee
new file mode 100644
index 00000000000..adaf1a836a8
--- /dev/null
+++ b/app/script/event/NotificationHandlingState.coffee
@@ -0,0 +1,25 @@
+#
+# Wire
+# Copyright (C) 2016 Wire Swiss GmbH
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+#
+
+window.z ?= {}
+z.event ?= {}
+
+z.event.NotificationHandlingState =
+  STREAM: 'z.event.NotificationHandlingState.STREAM'
+  RECOVERY: 'z.event.NotificationHandlingState.RECOVERY'
+  WEB_SOCKET: 'z.event.NotificationHandlingState.WEB_SOCKET'
diff --git a/app/script/event/NotificationService.coffee b/app/script/event/NotificationService.coffee
index 0e14e3f199c..43a1a59bf91 100644
--- a/app/script/event/NotificationService.coffee
+++ b/app/script/event/NotificationService.coffee
@@ -66,17 +66,14 @@ class z.event.NotificationService
   get_last_notification_id_from_db: =>
     return new Promise (resolve, reject) =>
       @storage_service.load @storage_service.OBJECT_STORE_AMPLIFY, @PRIMARY_KEY_LAST_NOTIFICATION
-      .then (record) =>
+      .then (record) ->
         if record?.value
           resolve record.value
         else
-          error_message = 'Last notification ID not found in storage'
-          @logger.log @logger.levels.WARN, error_message
-          reject new z.event.EventError error_message, z.event.EventError::TYPE.DATABASE_NOT_FOUND
+          reject new z.event.EventError z.event.EventError::TYPE.NO_LAST_ID
       .catch (error) =>
-        error_message = "Failed to get last notification ID from storage: #{error.message}"
-        @logger.log @logger.levels.ERROR, error_message, error
-        reject new z.event.EventError error_message, z.event.EventError::TYPE.DATABASE_FAILURE
+        @logger.log @logger.levels.ERROR, "Failed to get last notification ID from storage: #{error.message}", error
+        reject new z.event.EventError z.event.EventError::TYPE.DATABASE_FAILURE
 
   ###
   Load last notifications id from storage.
diff --git a/app/script/event/WebApp.coffee b/app/script/event/WebApp.coffee
index 99f833f825c..1ea7ab71b6f 100644
--- a/app/script/event/WebApp.coffee
+++ b/app/script/event/WebApp.coffee
@@ -67,7 +67,6 @@ z.event.WebApp =
     ACCESS_TOKEN:
       RENEW: 'wire.webapp.connection.access-token.renew'
       RENEWED: 'wire.webapp.connection.access-token.renewed'
-    RECONNECT: 'wire.webapp.connection.reconnect'
     ONLINE: 'wire.webapp.connection.online'
   CONVERSATION:
     DEBUG: 'wire.webapp.conversation.debug'
@@ -85,8 +84,6 @@ z.event.WebApp =
     ASSET:
       CANCEL: 'wire.webapp.conversation.asset.cancel'
     MESSAGE:
-      DELETE_SELF: 'wire.webapp.conversation.message.delete-self'
-      DELETE_EVERYONE: 'wire.webapp.conversation.message.delete-everyone'
       EDIT: 'wire.webapp.conversation.message.edit'
     IMAGE:
       SEND: 'wire.webapp.conversation.image.send'
@@ -162,7 +159,7 @@ z.event.WebApp =
   USER:
     UNBLOCKED: 'wire.webapp.user.unblocked'
     EVENT_FROM_BACKEND: 'wire.webapp.user.event-from-backend'
-  WARNINGS:
+  WARNING:
     SHOW: 'wire.webapp.warning.show'
     DISMISS: 'wire.webapp.warning.dismiss'
     MODAL: 'wire.webapp.warning.modal'
diff --git a/app/script/event/WebSocketService.coffee b/app/script/event/WebSocketService.coffee
index cdeb50fe5c2..36ccf22b856 100644
--- a/app/script/event/WebSocketService.coffee
+++ b/app/script/event/WebSocketService.coffee
@@ -111,7 +111,8 @@ class z.event.WebSocketService
   ###
   reconnect: (trigger) =>
     if not z.storage.get_value z.storage.StorageKey.AUTH.ACCESS_TOKEN.EXPIRATION
-      @logger.log @logger.levels.INFO, 'Access token has to be refreshed before reconnecting the WebSocket'
+      @logger.log @logger.levels.INFO, "Access token has to be refreshed before reconnecting the WebSocket triggered by '#{trigger}'"
+      amplify.unsubscribeAll z.event.WebApp.CONNECTION.ACCESS_TOKEN.RENEWED
       amplify.subscribe z.event.WebApp.CONNECTION.ACCESS_TOKEN.RENEWED, => @pending_reconnect trigger
       return amplify.publish z.event.WebApp.CONNECTION.ACCESS_TOKEN.RENEW
 
@@ -121,13 +122,13 @@ class z.event.WebSocketService
       @connect @on_notification
       .then =>
         @reconnect_count = 0
-        @logger.log @logger.levels.INFO, "Reconnected to WebSocket triggered by '#{trigger}'"
+        @logger.log @logger.levels.INFO, "Reconnect to WebSocket triggered by '#{trigger}'"
         @on_socket_reconnected()
 
     if @reconnect_count is 1
       reconnect()
     else
-      @reconnect_timeout_id = setTimeout ->
+      @reconnect_timeout_id = window.setTimeout ->
         reconnect()
       , RECONNECT_INTERVAL
 
@@ -145,7 +146,7 @@ class z.event.WebSocketService
       window.clearInterval @ping_interval_id
       window.clearTimeout @reconnect_timeout_id
     if reconnect
-      amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
+      amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
       @reconnect trigger
 
   # Send a WebSocket ping.
@@ -170,7 +171,7 @@ class z.event.WebSocketService
   @param trigger [z.event.WebSocketService::CHANGE_TRIGGER] Trigger of the reconnect
   ###
   on_socket_reconnected: =>
-    amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
+    amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
     @logger.log @logger.levels.WARN, 'Re-established WebSocket connection. Recovering from Notification Stream...'
     amplify.publish z.event.WebApp.CONNECTION.ONLINE
 
@@ -179,7 +180,7 @@ class z.event.WebSocketService
   @param trigger [z.event.WebSocketService::CHANGE_TRIGGER] Trigger of the connection close
   ###
   on_socket_closed: (trigger) ->
-    amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
+    amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
     error = new Error "WebSocket connection lost: #{trigger}"
     custom_data =
       network_status: navigator.onLine
diff --git a/app/script/links/LinkPreviewError.coffee b/app/script/links/LinkPreviewError.coffee
index 8b673b0c882..7a77aba16b6 100644
--- a/app/script/links/LinkPreviewError.coffee
+++ b/app/script/links/LinkPreviewError.coffee
@@ -23,19 +23,22 @@ class z.links.LinkPreviewError
   constructor: (type) ->
     @name = @constructor.name
     @stack = (new Error()).stack
-    @type = type
+    @type = type or z.links.LinkPreviewError::TYPE.UNKNOWN
 
-    switch @type
+    @message = switch @type
       when z.links.LinkPreviewError::TYPE.NOT_SUPPORTED
-        @message = 'Your client cannot render link previews using Open Graph data.'
+        'Your client cannot render link previews using Open Graph data.'
       when z.links.LinkPreviewError::TYPE.UNSUPPORTED_TYPE
-        @message = 'Open Graph data from the given link does not provide necessary attributes.'
+        'Open Graph data from the given link does not provide necessary attributes.'
       when z.links.LinkPreviewError::TYPE.NO_DATA_AVAILABLE
-        @message = 'Link does not provide Open Graph data.'
+        'Link does not provide Open Graph data.'
+      else
+        'Unknown LinkPreviewError'
 
   @:: = new Error()
   @::constructor = @
   @::TYPE =
+    NO_DATA_AVAILABLE: 'z.links.LinkPreviewError::TYPE.NO_DATA_AVAILABLE'
     NOT_SUPPORTED: 'z.links.LinkPreviewError::TYPE.NOT_SUPPORTED'
     UNSUPPORTED_TYPE: 'z.links.LinkPreviewError::TYPE.UNSUPPORTED_TYPE'
-    NO_DATA_AVAILABLE: 'z.links.LinkPreviewError::TYPE.NO_DATA_AVAILABLE'
+    UNKNOWN: 'z.links.LinkPreviewError::TYPE.UNKNOWN'
diff --git a/app/script/links/LinkPreviewRepository.coffee b/app/script/links/LinkPreviewRepository.coffee
index d1790b5e519..acb07257cac 100644
--- a/app/script/links/LinkPreviewRepository.coffee
+++ b/app/script/links/LinkPreviewRepository.coffee
@@ -36,6 +36,8 @@ class z.links.LinkPreviewRepository
       if data
         [url, offset] = data
         @get_link_preview url, offset
+        .catch (error) ->
+          throw error if error not instanceof z.links.LinkPreviewError
 
   ###
   Creates link preview for given link. This will upload associated image as asset and will
@@ -51,19 +53,16 @@ class z.links.LinkPreviewRepository
     .then =>
       if window.openGraph
         return @_fetch_open_graph_data url
-      else
-        throw new z.links.LinkPreviewError z.links.LinkPreviewError::TYPE.NOT_SUPPORTED
+      throw new z.links.LinkPreviewError z.links.LinkPreviewError::TYPE.NOT_SUPPORTED
     .then (data) ->
       open_graph_data = data
       if open_graph_data
-        return z.links.LinkPreviewProtoBuilder.build_from_open_graph_data data, url, offset
-      else
-        throw new z.links.LinkPreviewError z.links.LinkPreviewError::TYPE.NO_DATA_AVAILABLE
+        return z.links.LinkPreviewProtoBuilder.build_from_open_graph_data open_graph_data, url, offset
+      throw new z.links.LinkPreviewError z.links.LinkPreviewError::TYPE.NO_DATA_AVAILABLE
     .then (link_preview) ->
       if link_preview?
         return link_preview
-      else
-        throw new z.links.LinkPreviewError z.links.LinkPreviewError::TYPE.UNSUPPORTED_TYPE
+      throw new z.links.LinkPreviewError z.links.LinkPreviewError::TYPE.UNSUPPORTED_TYPE
     .then (link_preview) =>
       return @_fetch_preview_image link_preview, open_graph_data.image
 
@@ -86,9 +85,9 @@ class z.links.LinkPreviewRepository
   @param url [String]
   ###
   _fetch_open_graph_data: (link) ->
-    return new Promise (resolve, reject) ->
+    return new Promise (resolve) ->
       window.openGraph link, (error, data) ->
-        if error then reject error else resolve data
+        if error then resolve null else resolve data
 
   ###
   Upload open graph image as asset
diff --git a/app/script/localization/strings-de.coffee b/app/script/localization/strings-de.coffee
index fafa8fa26d3..3eed632abfd 100755
--- a/app/script/localization/strings-de.coffee
+++ b/app/script/localization/strings-de.coffee
@@ -138,6 +138,7 @@ z.string.de.call_banner_outgoing = 'Rufe %@.first_name an'
 # Warnings
 z.string.de.modal_button_cancel = 'Abbrechen'
 z.string.de.modal_button_ok = 'Ok'
+z.string.de.modal_button_send = 'Senden'
 
 # Block a user
 z.string.de.modal_block_conversation_headline = '%@.name blockieren?'
@@ -157,9 +158,9 @@ z.string.de.modal_call_second_incoming_headline = 'Anruf annehmen?'
 z.string.de.modal_call_second_incoming_message = 'Dein aktueller Anruf wird beendet.'
 z.string.de.modal_call_second_incoming_action = 'Annehmen'
 # Second ongoing call
-z.string.modal_call_second_ongoing_headline = 'Anruf auf einem anderen Gerät beenden?'
-z.string.modal_call_second_ongoing_message = 'Nur ein zeitgleicher Anruf möglich.'
-z.string.modal_call_second_ongoing_action = 'Beenden'
+z.string.de.modal_call_second_ongoing_headline = 'Anruf auf einem anderen Gerät beenden?'
+z.string.de.modal_call_second_ongoing_message = 'Nur ein zeitgleicher Anruf möglich.'
+z.string.de.modal_call_second_ongoing_action = 'Beenden'
 # Second outgoing call
 z.string.de.modal_call_second_outgoing_headline = 'Aktuellen Anruf beenden?'
 z.string.de.modal_call_second_outgoing_message = 'Nur ein zeitgleicher Anruf möglich.'
@@ -194,7 +195,7 @@ z.string.de.modal_leave_conversation_message = 'Die Personen werden benachrichti
 z.string.de.modal_leave_conversation_button = 'Verlassen'
 # Logout
 z.string.de.modal_logout_headline = 'Daten löschen?'
-z.string.de.modal_logout_message = 'Dies entfernt alle deine persönlichen Informationen und Unterhaltungen von diesem Gerät.'
+z.string.de.modal_logout_message = 'Deine persönlichen Daten und Unterhaltungen vollständig von diesem Gerät entfernen.'
 z.string.de.modal_logout_button = 'Abmelden'
 # New device
 z.string.de.modal_new_device_headline = '"%@.name" hat begonnen ein neues Gerät zu nutzen'
@@ -272,6 +273,8 @@ z.string.de.conversation_context_menu_edit = 'Bearbeiten'
 z.string.de.conversation_context_menu_delete = 'Für mich löschen'
 z.string.de.conversation_context_menu_delete_everyone = 'Für alle löschen'
 z.string.de.conversation_context_menu_download = 'Herunterladen'
+z.string.de.conversation_context_menu_like = 'Gefällt mir'
+z.string.de.conversation_context_menu_unlike = 'Gefällt mir nicht'
 z.string.de.conversation_delete_timestamp = 'Gelöscht um %@timestamp'
 z.string.de.conversation_edit_timestamp = 'Editiert um %@timestamp'
 
@@ -390,7 +393,7 @@ z.string.de.preferences_password = 'Passwort'
 z.string.de.preferences_password_reset = 'Passwort zurücksetzen'
 z.string.de.preferences_delete = 'Benutzerkonto löschen'
 z.string.de.preferences_email_sent = 'E-Mail gesendet'
-z.string.de.preferences_delete_info = 'Wir sende eine E-Mail an %email. Klicke den Link, um dein Benutzerkonto dauerhaft zu löschen.'
+z.string.de.preferences_delete_info = 'Wir senden eine E-Mail an %email. Klicke den Link, um dein Benutzerkonto dauerhaft zu löschen.'
 
 z.string.de.preferences_contacts = 'Kontakte'
 z.string.de.preferences_share_contacts = 'Aus Gmail importieren'
@@ -514,6 +517,7 @@ z.string.de.system_notification_member_leave_left = '%s.first_name hat die Unter
 z.string.de.system_notification_member_leave_removed_many = '%s.first_name hat %no Kontakte aus der Unterhaltung entfernt'
 z.string.de.system_notification_member_leave_removed_one = '%s.first_name hat %@.first_name aus der Unterhaltung entfernt'
 z.string.de.system_notification_ping = 'Hat gepingt'
+z.string.system_notification_reaction = '%reaction deine Nachricht'
 z.string.de.system_notification_voice_channel_activate = 'Ruft an'
 z.string.de.system_notification_voice_channel_deactivate = 'Hat versucht anzurufen'
 z.string.de.system_notification_shared_audio = 'Hat eine Audio-Nachricht geteilt'
diff --git a/app/script/localization/strings.coffee b/app/script/localization/strings.coffee
index 6d5c2edc346..d69a8188e49 100644
--- a/app/script/localization/strings.coffee
+++ b/app/script/localization/strings.coffee
@@ -138,6 +138,7 @@ z.string.call_banner_outgoing = 'Calling %@.first_name'
 # Warnings
 z.string.modal_button_cancel = 'Cancel'
 z.string.modal_button_ok = 'Ok'
+z.string.modal_button_send = 'Send'
 
 # Block a user
 z.string.modal_block_conversation_headline = 'Block %@.name?'
@@ -272,8 +273,11 @@ z.string.conversation_context_menu_edit = 'Edit'
 z.string.conversation_context_menu_delete = 'Delete for Me'
 z.string.conversation_context_menu_delete_everyone = 'Delete for Everyone'
 z.string.conversation_context_menu_download = 'Download'
+z.string.conversation_context_menu_like = 'Like'
+z.string.conversation_context_menu_unlike = 'Unlike'
 z.string.conversation_delete_timestamp = 'Deleted on %@timestamp'
 z.string.conversation_edit_timestamp = 'Edited on %@timestamp'
+z.string.conversation_likes_caption = '%@number people'
 
 # Conversation list
 z.string.conversation_list_archive = 'ARCHIVE'
@@ -514,6 +518,7 @@ z.string.system_notification_member_leave_left = '%s.first_name left the convers
 z.string.system_notification_member_leave_removed_many = '%s.first_name removed %no people from the conversation'
 z.string.system_notification_member_leave_removed_one = '%s.first_name removed %@.first_name from the conversation'
 z.string.system_notification_ping = 'Pinged'
+z.string.system_notification_reaction = '%reaction your message'
 z.string.system_notification_voice_channel_activate = 'Calling'
 z.string.system_notification_voice_channel_deactivate = 'Called'
 z.string.system_notification_shared_audio = 'Shared an audio message'
diff --git a/app/script/main/app.coffee b/app/script/main/app.coffee
index 168076d4bc9..719270bd946 100644
--- a/app/script/main/app.coffee
+++ b/app/script/main/app.coffee
@@ -171,7 +171,7 @@ class z.main.App
       @telemetry.add_statistic z.telemetry.app_init.AppInitStatisticsValue.CLIENT_TYPE, client_observable().type
       @repository.cryptography.current_client = client_observable
       @repository.event.current_client = client_observable
-      @repository.event.connect()
+      @repository.event.connect_web_socket()
       promises = [
         @repository.client.get_clients_for_self()
         @repository.user.init_properties()
@@ -280,7 +280,7 @@ class z.main.App
 
       token_promise.catch (error) =>
         if is_reload
-          if error.type is error.type is z.auth.AccessTokenError::TYPE.REQUEST_FORBIDDEN
+          if error.type is z.auth.AccessTokenError::TYPE.REQUEST_FORBIDDEN
             @logger.log @logger.levels.ERROR, "Session expired on page reload: #{error.message}", error
             Raygun.send new Error ('Session expired on page reload'), error
             @_redirect_to_login true
@@ -305,7 +305,7 @@ class z.main.App
   _subscribe_to_beforeunload: ->
     $(window).on 'beforeunload', =>
       @logger.log '\'window.onbeforeunload\' was triggered, so we will disconnect from the backend.'
-      @repository.event.disconnect z.event.WebSocketService::CHANGE_TRIGGER.PAGE_NAVIGATION
+      @repository.event.disconnect_web_socket z.event.WebSocketService::CHANGE_TRIGGER.PAGE_NAVIGATION
       @repository.call_center.state_handler.leave_call_on_beforeunload()
       @repository.storage.terminate 'window.onbeforeunload'
       return undefined
@@ -361,15 +361,15 @@ class z.main.App
     @logger.log @logger.levels.INFO, 'Internet connection regained. Re-establishing WebSocket connection...'
     @auth.client.execute_on_connectivity()
     .then =>
-      amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.NO_INTERNET
-      amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
-      @repository.event.reconnect z.event.WebSocketService::CHANGE_TRIGGER.ONLINE
+      amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.NO_INTERNET
+      amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.CONNECTIVITY_RECONNECT
+      @repository.event.reconnect_web_socket z.event.WebSocketService::CHANGE_TRIGGER.ONLINE
 
   # Reflect internet connection loss in the UI.
   on_internet_connection_lost: =>
     @logger.log @logger.levels.WARN, 'Internet connection lost'
-    @repository.event.disconnect z.event.WebSocketService::CHANGE_TRIGGER.OFFLINE
-    amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.NO_INTERNET
+    @repository.event.disconnect_web_socket z.event.WebSocketService::CHANGE_TRIGGER.OFFLINE
+    amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.NO_INTERNET
 
 
   ###############################################################################
@@ -385,7 +385,7 @@ class z.main.App
   logout: (cause, clear_data = false, session_expired = false) =>
     _logout = =>
       # Disconnect from our backend, end tracking and clear cached data
-      @repository.event.disconnect z.event.WebSocketService::CHANGE_TRIGGER.LOGOUT
+      @repository.event.disconnect_web_socket z.event.WebSocketService::CHANGE_TRIGGER.LOGOUT
       amplify.publish z.event.WebApp.ANALYTICS.SESSION.CLOSE
 
       # Clear Local Storage (but don't delete the cookie label if you were logged in with a permanent client)
diff --git a/app/script/storage/SkipError.coffee b/app/script/message/ReactionType.coffee
similarity index 77%
rename from app/script/storage/SkipError.coffee
rename to app/script/message/ReactionType.coffee
index ce16d39ab67..c79428e3641 100644
--- a/app/script/storage/SkipError.coffee
+++ b/app/script/message/ReactionType.coffee
@@ -17,13 +17,9 @@
 #
 
 window.z ?= {}
-z.storage ?= {}
+z.message ?= {}
 
-class z.storage.SkipError
-  constructor: (message) ->
-    @name = @constructor.name
-    @message = message
-    @stack = (new Error()).stack
-
-  @:: = new Error()
-  @::constructor = @
+# Enum for different reactions.
+z.message.ReactionType =
+  LIKE: '❤️'
+  NONE: ''
diff --git a/app/script/message/StatusType.coffee b/app/script/message/StatusType.coffee
new file mode 100644
index 00000000000..b0adb04c5b9
--- /dev/null
+++ b/app/script/message/StatusType.coffee
@@ -0,0 +1,28 @@
+#
+# Wire
+# Copyright (C) 2016 Wire Swiss GmbH
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+#
+
+window.z ?= {}
+z.message ?= {}
+
+# Enum for different confirmation types.
+z.message.SendingStatus =
+  FAILED: 0
+  SENDING: 1
+  SENT: 2
+  DELIVERED: 3
+  READ: 4
diff --git a/app/script/message/SuperType.coffee b/app/script/message/SuperType.coffee
index a771a6c8679..637a17629a9 100644
--- a/app/script/message/SuperType.coffee
+++ b/app/script/message/SuperType.coffee
@@ -31,6 +31,7 @@ z.message.SuperType =
   LOCATION: 'location'
   MEMBER: 'member'
   PING: 'ping'
+  REACTION: 'reaction'
   SPECIAL: 'special'
   SYSTEM: 'system'
   UNABLE_TO_DECRYPT: 'unable-to-decrypt'
diff --git a/app/script/storage/StorageError.coffee b/app/script/storage/StorageError.coffee
index f28e928afeb..5a828d2ee63 100644
--- a/app/script/storage/StorageError.coffee
+++ b/app/script/storage/StorageError.coffee
@@ -1,16 +1,57 @@
+#
+# Wire
+# Copyright (C) 2016 Wire Swiss GmbH
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+#
+
 window.z ?= {}
 z.storage ?= {}
 
 class z.storage.StorageError
-  constructor: (message) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message or @::TYPE.UNKNOWN
     @stack = (new Error()).stack
+    @type = type or z.storage.StorageError::TYPE.UNKNOWN
+
+    @message = switch @type
+      when z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND
+        'Data store not found'
+      when z.storage.StorageError::TYPE.FAILED_TO_OPEN
+        'Failed to open database'
+      when z.storage.StorageError::TYPE.INVALID_TIMESTAMP
+        'Invalid timestamp'
+      when z.storage.StorageError::TYPE.NO_CONVERSATION_ID
+        'Missing conversation ID'
+      when z.storage.StorageError::TYPE.NO_SENDER_ID
+        'Missing sender ID'
+      when z.storage.StorageError::TYPE.NO_TIME
+        'Missing time'
+      when z.storage.StorageError::TYPE.SKIP_LOADING
+        'Skipped loading of sessions and pre-keys'
+      when z.storage.StorageError::TYPE.UNKNOWN
+        'Unknown StorageError'
 
   @:: = new Error()
   @::constructor = @
   @::TYPE = {
-    FAILED_TO_OPEN: 'Failed to open database'
-    INVALID_TIMESTAMP: 'Invalid timestamp'
-    UNKNOWN: 'Unknown storage error'
+    DATA_STORE_NOT_FOUND: 'z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND'
+    FAILED_TO_OPEN: 'z.storage.StorageError::TYPE.FAILED_TO_OPEN'
+    INVALID_TIMESTAMP: 'z.storage.StorageError::TYPE.INVALID_TIMESTAMP'
+    NO_CONVERSATION_ID: 'z.storage.StorageError::TYPE.NO_CONVERSATION_ID'
+    NO_SENDER_ID: 'z.storage.StorageError::TYPE.NO_SENDER_ID'
+    NO_TIME: 'z.storage.StorageError::TYPE.NO_TIME'
+    SKIP_LOADING: 'z.storage.StorageError:TYPE.SKIP_SESSIONS'
+    UNKNOWN: 'z.storage.StorageError::TYPE.UNKNOWN'
   }
diff --git a/app/script/storage/StorageRepository.coffee b/app/script/storage/StorageRepository.coffee
index 1c278cd6ed1..c0c1f20198e 100644
--- a/app/script/storage/StorageRepository.coffee
+++ b/app/script/storage/StorageRepository.coffee
@@ -70,7 +70,7 @@ class z.storage.StorageRepository extends cryptobox.CryptoboxStore
       .then (local_identity) =>
         return {} if not local_identity
         if skip_sessions
-          throw new z.storage.SkipError 'Skipped loading of sessions and pre-keys'
+          throw new z.storage.StorageError z.storage.StorageError::TYPE.SKIP_LOADING
         else
           return @_load_sessions()
       .then =>
@@ -79,7 +79,7 @@ class z.storage.StorageRepository extends cryptobox.CryptoboxStore
         @logger.log @logger.levels.INFO, 'Initialized repository'
         resolve @
       .catch (error) =>
-        if error instanceof z.storage.SkipError
+        if error.type is z.storage.StorageError::TYPE.SKIP_LOADING
           @logger.log "Initialized repository with the following exception: #{error.message}"
           resolve @
         else
@@ -202,62 +202,17 @@ class z.storage.StorageRepository extends cryptobox.CryptoboxStore
   # Conversation Events
   ###############################################################################
 
-  ###
-  Construct a unique primary key.
-
-  @param conversation_id [String] ID of conversation
-  @param sender_id [String] ID of message sender
-  @param time [String] Time in ISO format to create timestamp from
-  @return [String] Generated primary key
-  ###
-  construct_primary_key: (conversation_id, sender_id = @storage_service.user_id, time) ->
-    timestamp = new Date(time).getTime()
-    throw new z.storage.StorageError z.storage.StorageError::TYPE.INVALID_TIMESTAMP if window.isNaN timestamp
-    return "#{conversation_id}@#{sender_id}@#{timestamp}"
-
-  ###
-  Save a decrypted conversation event.
-
-  @param primary_key [String] Primary key to save the object with
-  @param otr_message_event [Object] JSON event to be stored
-  @param mapped_json [Object] OTR event mapped to it's decrypted counterpart
-  @return [Promise] Promise that resolves with the stored record
-  ###
-  save_decrypted_conversation_event: (primary_key, otr_message_event, mapped_json) ->
-    return new Promise (resolve, reject) =>
-      event_object =
-        raw: otr_message_event
-        meta:
-          timestamp: new Date(otr_message_event.time).getTime()
-          version: 1
-        mapped: mapped_json
-
-      # We don't need to keep ciphertext once it has been successfully decrypted
-      event_object.raw.data = undefined
-
-      store_name = @storage_service.OBJECT_STORE_CONVERSATION_EVENTS
-      @storage_service.save store_name, primary_key, event_object
-      .then (primary_key) -> resolve primary_key
-      .catch (error) -> reject error
-
   ###
   Save an unencrypted conversation event.
   @param event [Object] JSON event to be stored
   @return [Promise] Promise that resolves with the stored record
   ###
-  save_unencrypted_conversation_event: (event) ->
+  save_conversation_event: (event) ->
     return new Promise (resolve, reject) =>
-      primary_key = @construct_primary_key event.conversation, event.from, event.time
-
-      event_object =
-        raw: event
-        meta:
-          timestamp: new Date(event.time).getTime()
-          version: 1
-
+      primary_key = z.storage.StorageService.construct_primary_key event
       store_name = @storage_service.OBJECT_STORE_CONVERSATION_EVENTS
-      @storage_service.save store_name, primary_key, event_object
-      .then (primary_key) -> resolve primary_key
+      @storage_service.save store_name, primary_key, event
+      .then -> resolve event
       .catch (error) -> reject error
 
   ###
@@ -278,9 +233,9 @@ class z.storage.StorageRepository extends cryptobox.CryptoboxStore
   load_events_by_types: (event_types) ->
     return new Promise (resolve, reject) =>
       @storage_service.db[@storage_service.OBJECT_STORE_CONVERSATION_EVENTS]
-      .where 'raw.type'
+      .where 'type'
       .anyOf event_types
-      .sortBy 'raw.time'
+      .sortBy 'time'
       .then (records) ->
         resolve records
       .catch (error) =>
diff --git a/app/script/storage/StorageService.coffee b/app/script/storage/StorageService.coffee
index 01902e0875d..02efb0099ca 100644
--- a/app/script/storage/StorageService.coffee
+++ b/app/script/storage/StorageService.coffee
@@ -31,6 +31,20 @@ class z.storage.StorageService
   OBJECT_STORE_PREKEYS: 'prekeys'
   OBJECT_STORE_SESSIONS: 'sessions'
 
+  ###
+  Construct a unique primary key.
+  @param event [Object] Message event
+  @return [String] Generated primary key
+  ###
+  @construct_primary_key: (event) ->
+    throw new z.storage.StorageError z.storage.StorageError::TYPE.NO_CONVERSATION_ID if not event.conversation
+    throw new z.storage.StorageError z.storage.StorageError::TYPE.NO_SENDER_ID if not event.from
+    throw new z.storage.StorageError z.storage.StorageError::TYPE.NO_TIME if not event.time
+    timestamp = new Date(event.time).getTime()
+    throw new z.storage.StorageError z.storage.StorageError::TYPE.INVALID_TIMESTAMP if window.isNaN timestamp
+    return "#{event.conversation}@#{event.from}@#{timestamp}"
+
+
   constructor: ->
     @logger = new z.util.Logger 'z.storage.StorageService', z.config.LOGGER.OPTIONS
 
@@ -93,6 +107,15 @@ class z.storage.StorageService
         "#{@OBJECT_STORE_PREKEYS}": ''
         "#{@OBJECT_STORE_SESSIONS}": ''
 
+      version_5 =
+        "#{@OBJECT_STORE_AMPLIFY}": ''
+        "#{@OBJECT_STORE_CLIENTS}": ', meta.primary_key'
+        "#{@OBJECT_STORE_CONVERSATION_EVENTS}": ', conversation, time, type'
+        "#{@OBJECT_STORE_CONVERSATIONS}": ', id, last_event_timestamp'
+        "#{@OBJECT_STORE_KEYS}": ''
+        "#{@OBJECT_STORE_PREKEYS}": ''
+        "#{@OBJECT_STORE_SESSIONS}": ''
+
       @db = new Dexie @db_name
 
       @db.on 'blocked', =>
@@ -130,6 +153,15 @@ class z.storage.StorageService
           @db[@OBJECT_STORE_SESSIONS].update key, {id: key}
         transaction[@OBJECT_STORE_PREKEYS].toCollection().eachKey (key) =>
           @db[@OBJECT_STORE_PREKEYS].update key, {id: key}
+      @db.version(7).stores version_5
+      .upgrade (transaction) =>
+        @logger.log @logger.levels.WARN, 'Database upgrade to version 7', transaction
+        transaction[@OBJECT_STORE_CONVERSATION_EVENTS].toCollection().modify (event) ->
+          mapped_event = event.mapped or event.raw
+          delete event.mapped
+          delete event.raw
+          delete event.meta
+          $.extend event, mapped_event
 
       @db.open()
       .then =>
@@ -162,7 +194,7 @@ class z.storage.StorageService
           @logger.log @logger.levels.ERROR, "Failed to delete '#{primary_key}' from store '#{store_name}'", error
           reject error
       else
-        reject new Error "Data store '#{store_name}' not found"
+        reject new z.storage.StorageError z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND
 
   clear_all_stores: =>
     promises = (@delete_store store_name for store_name of @db._dbSchema)
@@ -209,7 +241,7 @@ class z.storage.StorageService
           @logger.log @logger.levels.ERROR, "Could not load objects from store '#{store_name}'", error
           reject error
       else
-        reject new Error "Data store '#{store_name}' not found"
+        reject new z.storage.StorageError z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND
 
   ###
   Returns an array of all keys in a given object store.
@@ -232,7 +264,7 @@ class z.storage.StorageService
             resolve accepted_keys
         .catch (error) -> reject error
       else
-        reject new Error "Data store '#{store_name}' not found"
+        reject new z.storage.StorageError z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND
 
   ###
   Loads persisted data via a promise.
@@ -252,7 +284,7 @@ class z.storage.StorageService
           @logger.log @logger.levels.ERROR, "Failed to load '#{primary_key}' from store '#{store_name}'", error
           reject error
       else
-        reject new Error "Data store '#{store_name}' not found"
+        reject new Error z.storage.StorageError z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND
 
   ###
   Loads all objects from an object store and returns them with their keys and values.
@@ -306,7 +338,7 @@ class z.storage.StorageService
           @logger.log @logger.levels.ERROR, "Failed to put '#{primary_key}' into store '#{store_name}'", error
           reject error
       else
-        reject new Error "Data store '#{store_name}' not found"
+        reject new z.storage.StorageError z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND
 
   ###
   Closes the database. This operation completes immediately and there is no returned Promise.
@@ -337,4 +369,4 @@ class z.storage.StorageService
           @logger.log @logger.levels.ERROR, "Failed to update '#{primary_key}' in store '#{store_name}'", error
           reject error
       else
-        reject new Error "Data store '#{store_name}' not found"
+        reject new z.storage.StorageError z.storage.StorageError::TYPE.DATA_STORE_NOT_FOUND
diff --git a/app/script/system_notification/SystemNotificationRepository.coffee b/app/script/system_notification/SystemNotificationRepository.coffee
index 38a99658337..674d875fc65 100644
--- a/app/script/system_notification/SystemNotificationRepository.coffee
+++ b/app/script/system_notification/SystemNotificationRepository.coffee
@@ -31,6 +31,7 @@ class z.SystemNotification.SystemNotificationRepository
     z.message.SuperType.CONTENT
     z.message.SuperType.MEMBER
     z.message.SuperType.PING
+    z.message.SuperType.REACTION
     z.message.SuperType.SYSTEM
   ]
 
@@ -83,11 +84,11 @@ class z.SystemNotification.SystemNotificationRepository
   request_permission: (on_permission_granted, on_permission_denied) ->
     return if not z.util.Environment.browser.supports.notifications
     if window.Notification.permission is z.util.BrowserPermissionType.DEFAULT
-      amplify.publish z.event.WebApp.WARNINGS.SHOW, z.ViewModel.WarningType.REQUEST_NOTIFICATION
+      amplify.publish z.event.WebApp.WARNING.SHOW, z.ViewModel.WarningType.REQUEST_NOTIFICATION
       # Note: The callback will be only triggered in Chrome.
       # If you ignore a permission request on Firefox, then the callback will not be triggered.
       window.Notification.requestPermission? (permission) ->
-        amplify.publish z.event.WebApp.WARNINGS.DISMISS, z.ViewModel.WarningType.REQUEST_NOTIFICATION
+        amplify.publish z.event.WebApp.WARNING.DISMISS, z.ViewModel.WarningType.REQUEST_NOTIFICATION
         if permission is z.util.BrowserPermissionType.GRANTED
           amplify.publish z.event.WebApp.ANALYTICS.EVENT,
             z.tracking.EventName.PERMISSION.ALLOW_NOTIFICATIONS, value: 'allow'
@@ -101,11 +102,11 @@ class z.SystemNotification.SystemNotificationRepository
   ###
   Set the muted state.
   @note Temporarily mute notifications on recovery from Notification Stream
-  @param muted [Boolean] Are sounds and notifications muted
+  @param handling_notifications [z.event.NotificationHandlingState] Updated notification handling state
   ###
   set_muted_state: (handling_notifications) =>
-    @muted = handling_notifications
-    @logger.log @logger.levels.INFO, "Setting muted state to: #{handling_notifications}"
+    @muted = handling_notifications is z.event.NotificationHandlingState.STREAM
+    @logger.log @logger.levels.INFO, "Set muted state to: #{@muted}"
 
   ###
   @param should_request [Boolean] True, when permission should be requested
@@ -273,15 +274,26 @@ class z.SystemNotification.SystemNotificationRepository
         }
 
   ###
-  Creates the notification body for ping and hot-ping.
-
+  Creates the notification body for ping.
   @private
-  @param message_et [z.entity.PingMessage] Ping message entity
   @return [String] Notification message body
   ###
-  _create_body_ping: (message_et) ->
+  _create_body_ping: ->
     return z.localization.Localizer.get_text z.string.system_notification_ping
 
+
+  ###
+  Creates the notification body for reaction.
+  @private
+  @param message_et [z.entity.Message] Fake reaction message entity
+  @return [String] Notification message body
+  ###
+  _create_body_reaction: (message_et) ->
+    return z.localization.Localizer.get_text {
+      id: z.string.system_notification_reaction
+      replace: {placeholder: '%reaction', content: message_et.reaction}
+    }
+
   ###
   Selects the type of system message that the notification body needs to be created for.
 
@@ -311,7 +323,9 @@ class z.SystemNotification.SystemNotificationRepository
       when z.message.SuperType.MEMBER
         return @_create_body_member_update message_et, conversation_et.is_group?()
       when z.message.SuperType.PING
-        return @_create_body_ping message_et
+        return @_create_body_ping()
+      when z.message.SuperType.REACTION
+        return @_create_body_reaction message_et
       when z.message.SuperType.SYSTEM
         return @_create_body_conversation_rename message_et
 
diff --git a/app/script/tracking/EventName.coffee b/app/script/tracking/EventName.coffee
index 242d27d5cd9..4a2bcc644fe 100644
--- a/app/script/tracking/EventName.coffee
+++ b/app/script/tracking/EventName.coffee
@@ -46,6 +46,7 @@ z.tracking.EventName =
     DELETED_MESSAGE: 'conversation.deleted_message'
     EDITED_MESSAGE: 'conversation.edited_message'
     SELECTED_MESSAGE: 'conversation.selected_message'
+    REACTED_TO_MESSAGE: 'conversation.reacted_to_message'
   MEDIA:
     COMPLETED_MEDIA_ACTION: 'media.completed_media_action'
     PLAYED_AUDIO_MESSAGE: 'media.played_audio_message'
diff --git a/app/script/tracking/EventTrackingRepository.coffee b/app/script/tracking/EventTrackingRepository.coffee
index 5fa4da29874..e67153182ba 100644
--- a/app/script/tracking/EventTrackingRepository.coffee
+++ b/app/script/tracking/EventTrackingRepository.coffee
@@ -258,11 +258,13 @@ class z.tracking.EventTrackingRepository
       if _.isObject error
         window.onerror.call @, error.message, error.fileName, error.lineNumber, error.columnNumber, error
       else
-        window.onerror.call @, error, undefined, undefined, undefined, error
+        window.onerror.call @, error, null, null, null
 
-      promise = event.promise
-      if promise
-        promise.catch => @logger.log @logger.levels.OFF, 'Handled uncaught Promise in error reporting'
+      rejected_promise = event.promise
+      if rejected_promise
+        window.setTimeout =>
+          rejected_promise.catch (error) => @logger.log @logger.levels.OFF, 'Handled uncaught Promise in error reporting', error
+        , 0
 
   _detach_promise_rejection_handler: ->
     window.onunhandledrejection = undefined
diff --git a/app/script/user/UserError.coffee b/app/script/user/UserError.coffee
index 1b7454aeb2c..7ad11ad0fac 100644
--- a/app/script/user/UserError.coffee
+++ b/app/script/user/UserError.coffee
@@ -20,16 +20,23 @@ window.z ?= {}
 z.user ?= {}
 
 class z.user.UserError
-  constructor: (message, type) ->
+  constructor: (type) ->
     @name = @constructor.name
-    @message = message
-    @type = type
     @stack = (new Error()).stack
+    @type = type or z.user.UserError::TYPE.UNKNOWN
+
+    @message = switch @type
+      when z.user.UserError::TYPE.PRE_KEY_NOT_FOUND
+        'Pre-key not found'
+      when z.user.UserError::TYPE.REQUEST_FAILURE
+        'User related backend request failure'
+      else
+        'Unknown UserError'
 
   @:: = new Error()
   @::constructor = @
   @::TYPE = {
-    NO_CLIENTS: 'z.user.UserError::TYPE.NO_CLIENTS'
     PRE_KEY_NOT_FOUND: 'z.user.UserError::TYPE.PRE_KEY_NOT_FOUND'
     REQUEST_FAILURE: 'z.user.UserError::TYPE.REQUEST_FAILURE'
+    UNKNOWN: 'z.user.UserError::TYPE.UNKNOWN'
   }
diff --git a/app/script/util/util.coffee b/app/script/util/util.coffee
index 4b2df9770ea..f897b772258 100644
--- a/app/script/util/util.coffee
+++ b/app/script/util/util.coffee
@@ -314,8 +314,25 @@ z.util.alias =
 
 
 z.util.add_blank_targets = (text_with_anchors) ->
-  return "#{text_with_anchors}".replace /rel="nofollow"/gi, 'target="_blank" rel="nofollow"'
+  return "#{text_with_anchors}".replace /rel="nofollow"/gi, 'target="_blank" rel="nofollow noopener noreferrer"'
 
+###
+Opens a new browser tab (target="_blank") with a given URL in a safe environment.
+
+@see https://mathiasbynens.github.io/rel-noopener/
+@param url [String] URL you want to open in a new browser tab
+###
+z.util.safe_window_open = (url) ->
+  if not url.match /^http[s]?:\/\//i
+    url = "http://#{url}"
+
+  if navigator.userAgent.indexOf('Electron') > -1
+    window.open url
+  else
+    new_window = window.open()
+    new_window.opener = null
+    new_window.location = url
+    return new_window
 
 z.util.auto_link_emails = (text) ->
   email_pattern = /([a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+)/gim
@@ -332,7 +349,7 @@ z.util.cut_last_characters = (message, amount) ->
 
 
 z.util.markup_links = (message) ->
-  return message.replace(/<a\s+href=/gi, '<a target="_blank" rel="nofollow" href=')
+  return message.replace(/<a\s+href=/gi, '<a target="_blank" rel="nofollow noopener noreferrer" href=')
 
 # Source: https://github.com/KyleAMathews/deepmerge/blob/master/index.js
 z.util.merge_objects = (target, source) ->
diff --git a/app/script/view_model/ActionsViewModel.coffee b/app/script/view_model/ActionsViewModel.coffee
index 44dd24f1bcd..059a81f7cf1 100644
--- a/app/script/view_model/ActionsViewModel.coffee
+++ b/app/script/view_model/ActionsViewModel.coffee
@@ -88,7 +88,7 @@ class z.ViewModel.ActionsViewModel
     .then (conversation_et) =>
       next_conversation_et = @conversation_repository.get_next_conversation conversation_et
       user_et = conversation_et.participating_user_ets()[0]
-      amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.BLOCK,
+      amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.BLOCK,
         data: user_et.first_name()
         action: => @user_repository.block_user user_et, ->
           amplify.publish z.event.WebApp.CONVERSATION.SWITCH, conversation_et, next_conversation_et
@@ -102,7 +102,7 @@ class z.ViewModel.ActionsViewModel
   click_on_clear_action: =>
     @_click_on_action()
     .then (conversation_et) =>
-      amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CLEAR,
+      amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CLEAR,
         data: conversation_et.display_name()
         conversation: conversation_et
         action: (leave = false) => @conversation_repository.clear_conversation conversation_et, leave
@@ -111,7 +111,7 @@ class z.ViewModel.ActionsViewModel
     @_click_on_action()
     .then (conversation_et) =>
       next_conversation_et = @conversation_repository.get_next_conversation conversation_et
-      amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.LEAVE,
+      amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.LEAVE,
         data: conversation_et.display_name()
         action: => @conversation_repository.leave_conversation conversation_et, next_conversation_et
 
diff --git a/app/script/view_model/AuthViewModel.coffee b/app/script/view_model/AuthViewModel.coffee
index 7ecb55dd045..34e21e0af6a 100644
--- a/app/script/view_model/AuthViewModel.coffee
+++ b/app/script/view_model/AuthViewModel.coffee
@@ -503,7 +503,7 @@ class z.ViewModel.AuthViewModel
 
   clicked_on_password: ->
     amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.PASSWORD_RESET, value: 'fromSignIn'
-    (window.open z.localization.Localizer.get_text z.string.url_password_reset)?.focus()
+    (z.util.safe_window_open z.localization.Localizer.get_text z.string.url_password_reset)?.focus()
 
   clicked_on_register: => @_set_hash z.auth.AuthView.MODE.ACCOUNT_REGISTER
 
@@ -552,13 +552,13 @@ class z.ViewModel.AuthViewModel
 
   clicked_on_terms: ->
     amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.NAVIGATION.OPENED_TERMS
-    (window.open z.localization.Localizer.get_text z.string.url_terms_of_use)?.focus()
+    (z.util.safe_window_open z.localization.Localizer.get_text z.string.url_terms_of_use)?.focus()
 
   clicked_on_verify_later: => @_authentication_successful()
 
   clicked_on_wire_link: ->
     amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.NAVIGATION.OPENED_WIRE_WEBSITE
-    (window.open z.localization.Localizer.get_text z.string.url_wire)?.focus()
+    (z.util.safe_window_open z.localization.Localizer.get_text z.string.url_wire)?.focus()
 
   keydown_phone_code: (view_model, event) =>
     combo_key = if z.util.Environment.os.win then event.ctrlKey else event.metaKey
diff --git a/app/script/view_model/ConversationInputViewModel.coffee b/app/script/view_model/ConversationInputViewModel.coffee
index 4d2a5734f31..9353a28d506 100644
--- a/app/script/view_model/ConversationInputViewModel.coffee
+++ b/app/script/view_model/ConversationInputViewModel.coffee
@@ -142,7 +142,7 @@ class z.ViewModel.ConversationInputViewModel
   upload_files: (files) =>
     pending_uploads = @conversation_repository.get_number_of_pending_uploads()
     if pending_uploads + files.length > z.config.MAXIMUM_ASSET_UPLOADS
-      amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.UPLOAD_PARALLEL,
+      amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.UPLOAD_PARALLEL,
         data: z.config.MAXIMUM_ASSET_UPLOADS
       return
 
@@ -152,7 +152,7 @@ class z.ViewModel.ConversationInputViewModel
           {size: file.size, type: file.type}
         amplify.publish z.event.WebApp.AUDIO.PLAY, z.audio.AudioType.ALERT
         setTimeout ->
-          amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.UPLOAD_TOO_LARGE,
+          amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.UPLOAD_TOO_LARGE,
             data: z.util.format_bytes(z.config.MAXIMUM_ASSET_FILE_SIZE)
         , 200
         return
@@ -177,7 +177,7 @@ class z.ViewModel.ConversationInputViewModel
     @list_not_bottom not is_scrolled_bottom
 
   on_window_click: (event) =>
-    return if $(event.target).closest(".conversation-input").length
+    return if $(event.target).closest('.conversation-input').length
     @cancel_edit()
 
   on_input_click: =>
@@ -188,7 +188,7 @@ class z.ViewModel.ConversationInputViewModel
     message = z.util.trim_line_breaks @input()
 
     if message.length > z.config.MAXIMUM_MESSAGE_LENGTH
-      amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.TOO_LONG_MESSAGE,
+      amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.TOO_LONG_MESSAGE,
         data: z.config.MAXIMUM_MESSAGE_LENGTH
       amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.CONVERSATION.CHARACTER_LIMIT_REACHED,
         characters: message.length
diff --git a/app/script/view_model/ConversationTitlebarViewModel.coffee b/app/script/view_model/ConversationTitlebarViewModel.coffee
index 179a9096449..64b318c77dc 100644
--- a/app/script/view_model/ConversationTitlebarViewModel.coffee
+++ b/app/script/view_model/ConversationTitlebarViewModel.coffee
@@ -83,7 +83,7 @@ class z.ViewModel.ConversationTitlebarViewModel
   click_on_video_button: =>
     return if not @conversation_et()
     if @conversation_et().is_group()
-      amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CALL_NO_VIDEO_IN_GROUP
+      amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CALL_NO_VIDEO_IN_GROUP
     else
       amplify.publish z.event.WebApp.CALL.STATE.TOGGLE, @conversation_et().id, true
 
diff --git a/app/script/view_model/MessageListViewModel.coffee b/app/script/view_model/MessageListViewModel.coffee
index 3760f2c9399..48ba4eb2160 100644
--- a/app/script/view_model/MessageListViewModel.coffee
+++ b/app/script/view_model/MessageListViewModel.coffee
@@ -316,7 +316,7 @@ class z.ViewModel.MessageListViewModel
     reset_progress = ->
       window.setTimeout ->
         message_et.is_resetting_session false
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.SESSION_RESET
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.SESSION_RESET
       , 550
 
     message_et.is_resetting_session true
@@ -479,6 +479,12 @@ class z.ViewModel.MessageListViewModel
     if message_et.has_asset()
       entries.push {label: z.string.conversation_context_menu_download, action: 'download'}
 
+    if message_et.is_reactable() and not @conversation().removed_from_conversation()
+      if message_et.is_liked()
+        entries.push {label: z.string.conversation_context_menu_unlike, action: 'react'}
+      else
+        entries.push {label: z.string.conversation_context_menu_like, action: 'react'}
+
     if message_et.is_editable() and not @conversation().removed_from_conversation()
       entries.push {label: z.string.conversation_context_menu_edit, action: 'edit'}
 
@@ -513,13 +519,17 @@ class z.ViewModel.MessageListViewModel
 
     switch action
       when 'delete'
-        message_et?.delete()
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.DELETE_MESSAGE,
+          action: => @conversation_repository.delete_message @conversation(), message_et
       when 'delete-everyone'
-        message_et?.delete_everyone()
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.DELETE_EVERYONE_MESSAGE,
+          action: => @conversation_repository.delete_message_everyone @conversation(), message_et
       when 'download'
         message_et?.get_first_asset()?.download()
       when 'edit'
-        message_et?.edit()
+        amplify.publish z.event.WebApp.CONVERSATION.MESSAGE.EDIT, message_et
+      when 'react'
+        @click_on_like message_et, false
 
   ###
   Shows detail image view.
@@ -534,3 +544,32 @@ class z.ViewModel.MessageListViewModel
   click_on_cancel_request: (message_et) =>
     next_conversation_et = @conversation_repository.get_next_conversation @conversation_repository.active_conversation()
     @user_repository.cancel_connection_request message_et.other_user(), next_conversation_et
+
+  click_on_like: (message_et, button = true) =>
+    return if @conversation().removed_from_conversation()
+
+    reaction = if message_et.is_liked() then z.message.ReactionType.NONE else z.message.ReactionType.LIKE
+    message_et.is_liked not message_et.is_liked()
+
+    window.setTimeout =>
+      @conversation_repository.send_reaction @conversation(), message_et, reaction
+      @_track_reaction @conversation(), message_et, reaction, button
+    , 50
+
+  ###
+  Track reaction action.
+
+  @param conversation_et [z.entity.Conversation]
+  @param message_et [z.entity.Message]
+  @param reaction [z.message.ReactionType]
+  @param button [Boolean]
+  ###
+  _track_reaction: (conversation_et, message_et, reaction, button = true) ->
+    amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.CONVERSATION.REACTED_TO_MESSAGE,
+      conversation_type: z.tracking.helpers.get_conversation_type conversation_et
+      action: if reaction then 'like' else 'unlike'
+      with_bot: conversation_et.is_with_bot()
+      method: if button then 'button' else 'menu'
+      user: if message_et.user().is_me then 'sender' else 'receiver'
+      type: z.tracking.helpers.get_message_type message_et
+      reacted_to_last_message: conversation_et.get_last_message() is message_et
diff --git a/app/script/view_model/ModalsViewModel.coffee b/app/script/view_model/ModalsViewModel.coffee
index 53bf5fb0b8e..6c31f28ae2e 100644
--- a/app/script/view_model/ModalsViewModel.coffee
+++ b/app/script/view_model/ModalsViewModel.coffee
@@ -49,7 +49,7 @@ class z.ViewModel.ModalsViewModel
 
     @modals = {}
 
-    amplify.subscribe z.event.WebApp.WARNINGS.MODAL, @show_modal
+    amplify.subscribe z.event.WebApp.WARNING.MODAL, @show_modal
 
     ko.applyBindings @, document.getElementById element_id
 
diff --git a/app/script/view_model/SelfProfileViewModel.coffee b/app/script/view_model/SelfProfileViewModel.coffee
index 920ae66d18d..f1e32875d84 100644
--- a/app/script/view_model/SelfProfileViewModel.coffee
+++ b/app/script/view_model/SelfProfileViewModel.coffee
@@ -84,7 +84,7 @@ class z.ViewModel.SelfProfileViewModel
   logout: =>
     # TODO: Rely on client repository
     if @client_repository.current_client().type is z.client.ClientType.PERMANENT
-      amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.LOGOUT,
+      amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.LOGOUT,
         action: (clear_data) ->
           amplify.publish z.event.WebApp.SIGN_OUT, 'user_requested', clear_data
     else
@@ -92,7 +92,7 @@ class z.ViewModel.SelfProfileViewModel
       .then -> amplify.publish z.event.WebApp.SIGN_OUT, 'user_requested', true
 
   show_support_page: ->
-    (window.open z.string.url_support)?.focus()
+    (z.util.safe_window_open z.string.url_support)?.focus()
     amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.SETTINGS_MENU.SHOW_SUPPORT_PAGE
 
   toggle_about: ->
@@ -155,7 +155,7 @@ class z.ViewModel.SelfProfileViewModel
 
   on_show_new_clients: =>
     amplify.publish z.event.WebApp.SEARCH.BADGE.HIDE
-    amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CONNECTED_DEVICE,
+    amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CONNECTED_DEVICE,
       data: @new_clients()
       close: =>
         @new_clients.removeAll()
diff --git a/app/script/view_model/SettingsViewModel.coffee b/app/script/view_model/SettingsViewModel.coffee
index 78a45adc8ea..473a51d6f12 100644
--- a/app/script/view_model/SettingsViewModel.coffee
+++ b/app/script/view_model/SettingsViewModel.coffee
@@ -19,6 +19,11 @@
 window.z ?= {}
 z.ViewModel ?= {}
 
+DELETE_STATUS =
+  BUTTON: 'button'
+  DIALOG: 'dialog'
+  SENT: 'sent'
+
 SETTING =
   ALL: '0'
   NONE: '2'
@@ -63,7 +68,7 @@ class z.ViewModel.SettingsViewModel
     @data_setting = ko.observable()
     @data_setting.subscribe (setting) => @user_repository.save_property_data_settings setting
 
-    @delete_status = ko.observable 'button'
+    @delete_status = ko.observable DELETE_STATUS.BUTTON
     @delete_confirm_text = ko.observable ''
 
     @sound_setting = ko.observable()
@@ -113,21 +118,21 @@ class z.ViewModel.SettingsViewModel
       id: z.string.preferences_delete_info
       replace: {placeholder: '%email', content: @user().email()}
 
-    @delete_status 'dialog'
+    @delete_status DELETE_STATUS.DIALOG
 
   click_on_delete_send: ->
     @user_repository.delete_me()
-    @delete_status 'sent'
-    setTimeout =>
-      @delete_status 'button'
+    @delete_status DELETE_STATUS.SENT
+    window.setTimeout =>
+      @delete_status DELETE_STATUS.BUTTON
     , 5000
 
   click_on_delete_cancel: ->
-    @delete_status 'button'
+    @delete_status DELETE_STATUS.BUTTON
 
   click_on_reset_password: ->
     amplify.publish z.event.WebApp.ANALYTICS.EVENT, z.tracking.EventName.PASSWORD_RESET, value: 'fromProfile'
-    (window.open z.string.url_password_reset)?.focus()
+    (z.util.safe_window_open z.string.url_password_reset)?.focus()
 
   click_on_device: (client_et) =>
     @selected_device client_et
diff --git a/app/script/view_model/StartUIViewModel.coffee b/app/script/view_model/StartUIViewModel.coffee
index 4fe5667cdde..5a5afba28cb 100644
--- a/app/script/view_model/StartUIViewModel.coffee
+++ b/app/script/view_model/StartUIViewModel.coffee
@@ -194,7 +194,7 @@ class z.ViewModel.StartUIViewModel
     .catch (error) =>
       if error.type isnt z.connect.ConnectError::TYPE.NO_CONTACTS
         @logger.log @logger.levels.ERROR, "Importing contacts from '#{source}' failed: #{error.message}", error
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CONTACTS, action: =>
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CONTACTS, action: =>
           @import_contacts source, ui_identifier
     .then (error) =>
       @show_spinner false
diff --git a/app/script/view_model/WarningsViewModel.coffee b/app/script/view_model/WarningsViewModel.coffee
index 000a11cbe44..87e3300a0fb 100644
--- a/app/script/view_model/WarningsViewModel.coffee
+++ b/app/script/view_model/WarningsViewModel.coffee
@@ -78,8 +78,8 @@ class z.ViewModel.WarningsViewModel
     , @, deferEvaluation: true
     @warning_dimmed.extend rateLimit: 200
 
-    amplify.subscribe z.event.WebApp.WARNINGS.SHOW, @show_warning
-    amplify.subscribe z.event.WebApp.WARNINGS.DISMISS, @dismiss_warning
+    amplify.subscribe z.event.WebApp.WARNING.SHOW, @show_warning
+    amplify.subscribe z.event.WebApp.WARNING.DISMISS, @dismiss_warning
 
     ko.applyBindings @, document.getElementById element_id
 
@@ -90,8 +90,8 @@ class z.ViewModel.WarningsViewModel
 
     switch warning_to_remove
       when z.ViewModel.WarningType.REQUEST_MICROPHONE
-        amplify.publish z.event.WebApp.WARNINGS.MODAL, z.ViewModel.ModalType.CALLING,
-          action: -> (window.open z.localization.Localizer.get_text z.string.url_support_mic_access_denied)?.focus()
+        amplify.publish z.event.WebApp.WARNING.MODAL, z.ViewModel.ModalType.CALLING,
+          action: -> (z.util.safe_window_open z.localization.Localizer.get_text z.string.url_support_mic_access_denied)?.focus()
       when z.ViewModel.WarningType.REQUEST_NOTIFICATION
       # We block subsequent permission requests for notifications when the user ignores the request.
         amplify.publish z.event.WebApp.SYSTEM_NOTIFICATION.REQUEST_PERMISSION, false
diff --git a/app/style/common/colors.less b/app/style/common/colors.less
index 3da10955c38..1f602b24f1f 100644
--- a/app/style/common/colors.less
+++ b/app/style/common/colors.less
@@ -50,3 +50,15 @@
 .text-graphite-dark {.text(@graphite-dark)}
 .text-white {.text(#fff)}
 
+// fonts
+.font-size(@size) {
+  font-size: @size !important;
+}
+
+.font-size-xxs {.font-size(@font-size-xxs)}
+.font-size-xs {.font-size(@font-size-xs)}
+.font-size-sm {.font-size(@font-size-sm)}
+.font-size-md {.font-size(@font-size-md)}
+.font-size-lg {.font-size(@font-size-lg)}
+.font-size-xl {.font-size(@font-size-xl)}
+.font-size-xxl {.font-size(@font-size-xxl)}
diff --git a/app/style/common/like.less b/app/style/common/like.less
new file mode 100644
index 00000000000..a5fd1e0cee1
--- /dev/null
+++ b/app/style/common/like.less
@@ -0,0 +1,29 @@
+.like-button {
+  .circle(24px);
+  cursor: pointer;
+  position: relative;
+
+  > span {
+    .absolute-center(10px);
+    .font-size-xs;
+
+    &:first-child {
+      color: @graphite;
+    }
+
+    &:last-child {
+      color: @w-red;
+
+      opacity: 0;
+      transform: scale(6);
+      transition: all @animation-timing-fast @ease-out-quart;
+    }
+  }
+}
+
+.like-button-liked {
+  > span:last-child {
+    opacity: 1;
+    transform: scale(1);
+  }
+}
diff --git a/app/style/common/mixins.less b/app/style/common/mixins.less
index 1b036e5f1a2..d37df6d780c 100644
--- a/app/style/common/mixins.less
+++ b/app/style/common/mixins.less
@@ -122,6 +122,14 @@
   transform: translate(-50%, -50%);
 }
 
+.absolute-center(@size) {
+  position: absolute;
+  left: 50%;
+  top: 50%;
+  margin-left: -@size / 2;
+  margin-top: -@size / 2;
+}
+
 .flex-center {
   display: flex;
   align-items: center;
diff --git a/app/style/components/context-menu.less b/app/style/components/context-menu.less
index 7fe69c83b7c..c60cbaea493 100644
--- a/app/style/components/context-menu.less
+++ b/app/style/components/context-menu.less
@@ -18,6 +18,7 @@
  */
 
 context-menu {
+  cursor: pointer;
 
   .bubble {
     min-height: initial;
@@ -26,5 +27,4 @@ context-menu {
   .bubble-menu {
     font-family: @font-family-base;
   }
-
 }
diff --git a/app/style/conversation/message-list.less b/app/style/conversation/message-list.less
index a082ff0ab21..06c89f093b4 100644
--- a/app/style/conversation/message-list.less
+++ b/app/style/conversation/message-list.less
@@ -350,7 +350,7 @@
   }
 
   .iframe-container {
-    margin-bottom: 16px;
+    margin-bottom: 24px;
     margin-top: 16px;
 
     &.iframe-container-video {
@@ -372,6 +372,25 @@
   }
 }
 
+.message-body-like {
+  .flex-center;
+  position: absolute;
+  bottom: 0;
+  left: 0;
+  width: @conversation-message-sender-width;
+
+  .image-widescreen & {
+    bottom: 8px;
+  }
+}
+
+.message-body-like-icon {
+
+  .image-widescreen & {
+    background-color: #fff;
+  }
+}
+
 .message-asset-image {
   margin-top: 16px;
   margin-bottom: 24px;
@@ -401,3 +420,51 @@
     justify-content: center;
   }
 }
+
+// MESSAGE FOOTER
+.message-footer {
+  display: flex;
+  flex-wrap: wrap;
+  line-height: @avatar-diameter-xs;
+}
+
+.message-footer-icon {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  width: @conversation-message-sender-width;
+}
+
+.message-footer-label {
+  font-size: @font-size-xs;
+  display: flex;
+  align-items: center;
+
+  > * + * {
+    margin-left: 8px;
+  }
+}
+
+.message-footer-bottom {
+  display: flex;
+  margin-top: 4px;
+  margin-left: @conversation-message-sender-width;
+  width: 100%;
+
+  > * + * {
+    margin-left: 8px;
+  }
+}
+
+// hover
+.message-show-on-hover {
+  opacity: 0;
+  transition-property: opacity;
+  transition-timing-function: @ease-out-quart;
+  transition-duration: @animation-timing-fast;
+
+  .message:hover & {
+    opacity: 1;
+    transition-delay: @animation-timing-faster + .05;
+  }
+}
diff --git a/app/style/fonts/zeta-neue.css b/app/style/fonts/zeta-neue.css
index 62d0c3e1eef..fe4c85390b0 100755
--- a/app/style/fonts/zeta-neue.css
+++ b/app/style/fonts/zeta-neue.css
@@ -19,7 +19,7 @@
 
 @font-face {
   font-family: 'Wire';
-  src: url('/font/Wire.ttf?180716') format('truetype');
+  src: url('/font/Wire.ttf?hy9gt1') format('truetype');
   font-weight: normal;
   font-style: normal;
 }
@@ -156,6 +156,12 @@
 .icon-edit:before {
   content: "\e177";
 }
+.icon-like:before {
+  content: "\e183";
+}
+.icon-liked:before {
+  content: "\e184";
+}
 .icon-view:before {
   content: "\e185";
 }
diff --git a/app/style/main.less b/app/style/main.less
index 5dee9dd2946..51a0001a000 100644
--- a/app/style/main.less
+++ b/app/style/main.less
@@ -36,6 +36,7 @@
 @import "common/hide-controls";
 @import "common/hint";
 @import "common/label";
+@import "common/like";
 @import "common/mixins";
 @import "common/modal";
 @import "common/variables";
diff --git a/bower.json b/bower.json
index 6f0a33f4e98..63b44db9734 100644
--- a/bower.json
+++ b/bower.json
@@ -7,7 +7,7 @@
     "cryptojs": "https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/crypto-js/CryptoJS%20v3.1.2.zip",
     "highlight.js": "https://github.com/isagalaev/highlight.js.git#9.4.0",
     "dexie": "https://github.com/dfahlander/Dexie.js.git#1.4.1",
-    "generic-message-proto": "https://github.com/wireapp/generic-message-proto.git#1.14.0",
+    "generic-message-proto": "https://github.com/wireapp/generic-message-proto.git#1.17.0",
     "iframeTracker-jquery": "https://github.com/vincepare/iframeTracker-jquery.git#1.1.0",
     "jquery": "https://github.com/jquery/jquery.git#2.1.4",
     "keyboardjs": "https://github.com/RobertWHurst/KeyboardJS.git#2.2.1",
@@ -19,14 +19,14 @@
     "phone-format": "https://github.com/albeebe/phoneformat.js.git#v1.0.3",
     "platform.js": "https://github.com/bestiejs/platform.js.git#0870795f0c277a33cc2078a96e74434f89aa11d8",
     "protobuf": "https://github.com/gregor/protobuf.js.git#32ada41d3c963bd5f43d7cdadced2d6d2ccd082a",
-    "raygun4js": "https://github.com/MindscapeHQ/raygun4js.git#2.3.2",
+    "raygun4js": "https://github.com/MindscapeHQ/raygun4js.git#2.3.4",
     "twitter-text": "https://github.com/twitter/twitter-text.git#v1.13.4",
     "uint32": "https://github.com/fxa/uint32.js.git#0.2.1",
     "underscore": "https://github.com/jashkenas/underscore.git#1.8.3",
     "uuid": "https://github.com/LiosK/UUID.js.git#v3.3.0",
     "wire-audio-files": "https://github.com/wireapp/wire-audio-files.git#1.0.0",
     "webapp-module-bubble": "https://github.com/wireapp/webapp-module-bubble.git#1.0.0",
-    "webapp-module-external": "https://github.com/wireapp/webapp-module-external.git#1.0.0",
+    "webapp-module-external": "https://github.com/wireapp/webapp-module-external.git#1.0.1",
     "webapp-module-image-compressor": "https://github.com/wireapp/webapp-module-image-compressor.git#1.0.0",
     "webapp-module-image-rotation": "https://github.com/wireapp/webapp-module-image-rotation.git#1.0.0",
     "webapp-module-logger": "https://github.com/wireapp/webapp-module-logger.git#1.0.0",
diff --git a/test/unit_tests/calling/CallCenterSpec.coffee b/test/unit_tests/calling/CallCenterSpec.coffee
index 47f9ea94ba1..a52eb73ca74 100644
--- a/test/unit_tests/calling/CallCenterSpec.coffee
+++ b/test/unit_tests/calling/CallCenterSpec.coffee
@@ -86,7 +86,7 @@ describe 'z.calling.CallCenter', ->
   beforeAll (done) ->
     test_factory.exposeCallingActors()
     .then ->
-      amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, false
+      amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, z.event.NotificationHandlingState.WEB_SOCKET
 
       # User entities
       build_user = (name, is_self = false) ->
@@ -403,7 +403,7 @@ describe 'z.calling.CallCenter', ->
       .then done.fail
       .catch (error) ->
         expect(error).toEqual jasmine.any z.calling.CallError
-        expect(error.message).toBe z.calling.CallError::TYPE.CONVERSATION_TOO_BIG
+        expect(error.type).toBe z.calling.CallError::TYPE.CONVERSATION_TOO_BIG
         expect(call_center.media_stream_handler.release_media_streams).toHaveBeenCalled()
         done()
       server.requests[0].respond 409, 'Content-Type': 'application/json', JSON.stringify error_payload
@@ -421,7 +421,7 @@ describe 'z.calling.CallCenter', ->
       .then done.fail
       .catch (error) ->
         expect(error).toEqual jasmine.any z.calling.CallError
-        expect(error.message).toBe z.calling.CallError::TYPE.VOICE_CHANNEL_FULL
+        expect(error.type).toBe z.calling.CallError::TYPE.VOICE_CHANNEL_FULL
         expect(call_center.media_stream_handler.release_media_streams).toHaveBeenCalled()
         done()
       server.requests[0].respond 409, 'Content-Type': 'application/json', JSON.stringify error_payload
@@ -438,7 +438,7 @@ describe 'z.calling.CallCenter', ->
       .then done.fail
       .catch (error) ->
         expect(error).toEqual jasmine.any z.calling.CallError
-        expect(error.message).toBe z.calling.CallError::TYPE.CONVERSATION_EMPTY
+        expect(error.type).toBe z.calling.CallError::TYPE.CONVERSATION_EMPTY
         expect(call_center.media_stream_handler.release_media_streams).toHaveBeenCalled()
         done()
       server.requests[0].respond 400, 'Content-Type': 'application/json', JSON.stringify error_payload
diff --git a/test/unit_tests/calling/handler/MediaStreamHandlerSpec.coffee b/test/unit_tests/calling/handler/MediaStreamHandlerSpec.coffee
index 8a7a20270c1..3a34f723c0f 100644
--- a/test/unit_tests/calling/handler/MediaStreamHandlerSpec.coffee
+++ b/test/unit_tests/calling/handler/MediaStreamHandlerSpec.coffee
@@ -90,7 +90,7 @@ describe 'z.calling.handler.MediaStreamHandler', ->
       .then done.fail
       .catch (error) ->
         expect(error).toEqual jasmine.any z.calling.CallError
-        expect(error.message).toBe z.calling.CallError::TYPE.NO_AUDIO_STREAM_FOUND
+        expect(error.type).toBe z.calling.CallError::TYPE.NO_AUDIO_STREAM_FOUND
         done()
 
 
diff --git a/test/unit_tests/client/ClientRepositorySpec.coffee b/test/unit_tests/client/ClientRepositorySpec.coffee
index db256be0cae..8fab99030f8 100644
--- a/test/unit_tests/client/ClientRepositorySpec.coffee
+++ b/test/unit_tests/client/ClientRepositorySpec.coffee
@@ -133,7 +133,7 @@ describe 'z.client.ClientRepository', ->
       .then done.fail
       .catch (error) ->
         expect(error).toEqual jasmine.any Error
-        expect(error.message).toEqual 'Expected unit test error'
+        expect(error.type).toBe z.client.ClientError::TYPE.DATABASE_FAILURE
         done()
 
   describe '_construct_primary_key', ->
@@ -170,7 +170,7 @@ describe 'z.client.ClientRepository', ->
     it 'throws an error on Electron if no current client', ->
       z.util.Environment.electron = true
       function_call = -> client_repository.is_current_client_permanent()
-      expect(function_call).toThrowError z.client.ClientError, 'No current client'
+      expect(function_call).toThrowError z.client.ClientError, 'Local client is not yet set'
 
     it 'returns true if current client is permanent', ->
       client_repository.current_client new z.client.Client {type: z.client.ClientType.PERMANENT}
@@ -184,7 +184,7 @@ describe 'z.client.ClientRepository', ->
 
     it 'throws an error if no current client', ->
       function_call = -> client_repository.is_current_client_permanent()
-      expect(function_call).toThrowError z.client.ClientError, 'No current client'
+      expect(function_call).toThrowError z.client.ClientError, 'Local client is not yet set'
 
   describe '_is_current_client', ->
     beforeEach -> client_repository.current_client undefined
@@ -207,7 +207,7 @@ describe 'z.client.ClientRepository', ->
 
     it 'throws an error if current client is not set', ->
       function_call = -> client_repository._is_current_client user_id, client_id
-      expect(function_call).toThrowError z.client.ClientError, 'No current client'
+      expect(function_call).toThrowError z.client.ClientError, 'Local client is not yet set'
 
     it 'throws an error if client ID is not specified', ->
       client_repository.current_client new z.client.Client()
diff --git a/test/unit_tests/conversation/ConversationRepositorySpec.coffee b/test/unit_tests/conversation/ConversationRepositorySpec.coffee
index a37379c1f6b..b7bf431d055 100644
--- a/test/unit_tests/conversation/ConversationRepositorySpec.coffee
+++ b/test/unit_tests/conversation/ConversationRepositorySpec.coffee
@@ -60,6 +60,7 @@ describe 'z.conversation.ConversationRepository', ->
 
     test_factory.exposeConversationActors()
     .then (conversation_repository) ->
+      amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, z.event.NotificationHandlingState.WEB_SOCKET
       storage_service = conversation_repository.conversation_service.storage_service
 
       conversation_et = _generate_conversation z.conversation.ConversationType.SELF
@@ -122,7 +123,7 @@ describe 'z.conversation.ConversationRepository', ->
     member_join_event = null
 
     beforeEach ->
-      spyOn(conversation_repository, 'member_join').and.callThrough()
+      spyOn(conversation_repository, '_on_member_join').and.callThrough()
 
       member_join_event = {
         "conversation": conversation_et.id,
@@ -135,7 +136,7 @@ describe 'z.conversation.ConversationRepository', ->
 
     it 'processes member join if joining a group conversation', ->
       conversation_repository.on_conversation_event member_join_event
-      expect(conversation_repository.member_join).toHaveBeenCalled()
+      expect(conversation_repository._on_member_join).toHaveBeenCalled()
 
     it 'ignores member join if joining a one2on2 conversation', ->
 
@@ -146,7 +147,7 @@ describe 'z.conversation.ConversationRepository', ->
       user_repository.connections.push connection_et_a
 
       conversation_repository.on_conversation_event member_join_event
-      expect(conversation_repository.member_join).not.toHaveBeenCalled()
+      expect(conversation_repository._on_member_join).not.toHaveBeenCalled()
 
     # @todo Cached conversation events are not properly reset anymore
     xit 'caches events while getting the conversation from the backend', ->
@@ -307,9 +308,12 @@ describe 'z.conversation.ConversationRepository', ->
 
       conversation_repository.delete_message_everyone conversation_et, message_to_delete_et
       .then done.fail
-      .catch done
+      .catch (error) ->
+        expect(error).toEqual jasmine.any z.conversation.ConversationError
+        expect(error.type).toBe z.conversation.ConversationError::TYPE.WRONG_USER
+        done()
 
-    it 'sends delete and deletes message for own messages', (done) ->
+    xit 'sends delete and deletes message for own messages', (done) ->
       user_et = new z.entity.User()
       user_et.is_me = true
       message_to_delete_et = new z.entity.Message()
@@ -317,14 +321,14 @@ describe 'z.conversation.ConversationRepository', ->
       message_to_delete_et.user user_et
       conversation_et.add_message message_to_delete_et
 
-      expect(conversation_et.get_message_by_id(message_to_delete_et.id)).toBeDefined()
+      expect(conversation_et.get_message_by_id message_to_delete_et.id).toBeDefined()
       conversation_repository.delete_message_everyone conversation_et, message_to_delete_et
       .then ->
-        expect(conversation_et.get_message_by_id(message_to_delete_et.id)).not.toBeDefined()
+        expect(conversation_et.get_message_by_id message_to_delete_et.id).not.toBeDefined()
         done()
       .catch done.fail
 
-  describe 'message_hidden', ->
+  describe '_on_message_hidden', ->
 
     conversation_et = null
     message_to_hide_et = null
@@ -346,10 +350,10 @@ describe 'z.conversation.ConversationRepository', ->
           conversation_id: conversation_et.id
         from: z.util.create_random_uuid()
         time: new Date().toISOString()
-        type: z.event.Backend.CONVERSATION.MESSAGE_HIDDEN
+        type: z.event.Client.CONVERSATION.MESSAGE_HIDDEN
 
       expect(conversation_et.get_message_by_id(message_to_hide_et.id)).toBeDefined()
-      conversation_repository.message_hidden event
+      conversation_repository._on_message_hidden event
       .then done.fail
       .catch ->
         expect(conversation_et.get_message_by_id(message_to_hide_et.id)).toBeDefined()
@@ -364,16 +368,16 @@ describe 'z.conversation.ConversationRepository', ->
           conversation_id: conversation_et.id
         from: user_repository.self().id
         time: new Date().toISOString()
-        type: z.event.Backend.CONVERSATION.MESSAGE_HIDDEN
+        type: z.event.Client.CONVERSATION.MESSAGE_HIDDEN
 
       expect(conversation_et.get_message_by_id(message_to_hide_et.id)).toBeDefined()
-      conversation_repository.message_hidden event
+      conversation_repository._on_message_hidden event
       .then ->
         expect(conversation_et.get_message_by_id(message_to_hide_et.id)).not.toBeDefined()
         done()
       .catch done.fail
 
-  describe 'message_deleted', ->
+  describe '_on_message_deleted', ->
 
     conversation_et = null
     message_to_delete_et = null
@@ -387,7 +391,7 @@ describe 'z.conversation.ConversationRepository', ->
       message_to_delete_et.from = user_repository.self().id
       conversation_et.add_message message_to_delete_et
 
-      spyOn(conversation_repository, 'get_message_from_db').and.returnValue Promise.resolve message_to_delete_et
+      spyOn(conversation_repository, 'get_message_in_conversation_by_id').and.returnValue Promise.resolve message_to_delete_et
       spyOn conversation_repository, '_add_delete_message'
 
     it 'deletes message if user is self', (done) ->
@@ -398,10 +402,10 @@ describe 'z.conversation.ConversationRepository', ->
           message_id: message_to_delete_et.id
         from: user_repository.self().id
         time: new Date().toISOString()
-        type: z.event.Backend.CONVERSATION.MESSAGE_DELETE
+        type: z.event.Client.CONVERSATION.MESSAGE_DELETE
 
       expect(conversation_et.get_message_by_id(message_to_delete_et.id)).toBeDefined()
-      conversation_repository.message_deleted conversation_et, event
+      conversation_repository._on_message_deleted conversation_et, event
       .then ->
         expect(conversation_et.get_message_by_id(message_to_delete_et.id)).not.toBeDefined()
         expect(conversation_repository._add_delete_message).not.toHaveBeenCalled()
@@ -419,10 +423,10 @@ describe 'z.conversation.ConversationRepository', ->
           message_id: message_to_delete_et.id
         from: other_user_id
         time: new Date().toISOString()
-        type: z.event.Backend.CONVERSATION.MESSAGE_DELETE
+        type: z.event.Client.CONVERSATION.MESSAGE_DELETE
 
       expect(conversation_et.get_message_by_id(message_to_delete_et.id)).toBeDefined()
-      conversation_repository.message_deleted conversation_et, event
+      conversation_repository._on_message_deleted conversation_et, event
       .then ->
         expect(conversation_et.get_message_by_id(message_to_delete_et.id)).not.toBeDefined()
         expect(conversation_repository._add_delete_message).toHaveBeenCalled()
@@ -483,10 +487,10 @@ describe 'z.conversation.ConversationRepository', ->
         from: z.util.create_random_uuid()
         time: Date.now()
         id: message_et.id
-        type: z.event.Backend.CONVERSATION.ASSET_UPLOAD_COMPLETE
+        type: z.event.Client.CONVERSATION.ASSET_UPLOAD_COMPLETE
         conversation: conversation_et.id
 
-      conversation_repository.asset_upload_complete conversation_et, event
+      conversation_repository._on_asset_upload_complete conversation_et, event
 
       expect(conversation_service.update_asset_as_uploaded_in_db).toHaveBeenCalled()
       expect(message_et.assets()[0].original_resource().otr_key).toBe event.data.otr_key
@@ -503,10 +507,10 @@ describe 'z.conversation.ConversationRepository', ->
         from: z.util.create_random_uuid()
         time: Date.now()
         id: message_et.id
-        type: z.event.Backend.CONVERSATION.ASSET_PREVIEW
+        type: z.event.Client.CONVERSATION.ASSET_PREVIEW
         conversation: conversation_et.id
 
-      conversation_repository.asset_preview conversation_et, event
+      conversation_repository._on_asset_preview conversation_et, event
 
       expect(conversation_service.update_asset_preview_in_db).toHaveBeenCalled()
       expect(message_et.assets()[0].preview_resource().otr_key).toBe event.data.otr_key
@@ -521,10 +525,10 @@ describe 'z.conversation.ConversationRepository', ->
         from: z.util.create_random_uuid()
         time: Date.now()
         id: message_et.id
-        type: z.event.Backend.CONVERSATION.ASSET_UPLOAD_FAILED
+        type: z.event.Client.CONVERSATION.ASSET_UPLOAD_FAILED
         conversation: conversation_et.id
 
-      conversation_repository.asset_upload_failed conversation_et, event
+      conversation_repository._on_asset_upload_failed conversation_et, event
 
       expect(conversation_service.update_asset_as_failed_in_db).toHaveBeenCalled()
       expect(message_et.assets()[0].status()).toBe z.assets.AssetTransferState.UPLOAD_FAILED
@@ -538,10 +542,10 @@ describe 'z.conversation.ConversationRepository', ->
         from: z.util.create_random_uuid()
         time: Date.now()
         id: message_et.id
-        type: z.event.Backend.CONVERSATION.ASSET_UPLOAD_FAILED
+        type: z.event.Client.CONVERSATION.ASSET_UPLOAD_FAILED
         conversation: conversation_et.id
 
-      conversation_repository.asset_upload_failed conversation_et, event
+      conversation_repository._on_asset_upload_failed conversation_et, event
 
       expect(conversation_service.delete_message_from_db).toHaveBeenCalledWith conversation_et.id, message_et.id
       expect(conversation_et.get_message_by_id message_et.id).toBeUndefined()
@@ -708,11 +712,11 @@ describe 'z.conversation.ConversationRepository', ->
     it 'gets messages which are not broken by design', (done) ->
       conversation_et = new z.entity.Conversation z.util.create_random_uuid()
       #@formatter:off
-      bad_message = {"raw":{"from":"532af01e-1e24-4366-aacf-33b67d4ee376","type":"conversation.otr-message-add","conversation":conversation_et.id},"meta":{"timestamp":null,"version":1},"mapped":{"conversation":"573b6978-7700-443e-9ce5-ff78b35ac590","id":"aeac8355-739b-4dfc-a119-891a52c6a8dc","from":"532af01e-1e24-4366-aacf-33b67d4ee376","data":{"content":"Hello World :)","nonce":"aeac8355-739b-4dfc-a119-891a52c6a8dc"},"type":"conversation.message-add"}}
-      good_message = {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:33.389Z","type":"conversation.otr-message-add","conversation":conversation_et.id},"meta":{"timestamp":1470317313389,"version":1},"mapped":{"conversation":"573b6978-7700-443e-9ce5-ff78b35ac590","id":"5a8cd79a-82bb-49ca-a59e-9a8e76df77fb","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:33.389Z","data":{"content":"Fifth message","nonce":"5a8cd79a-82bb-49ca-a59e-9a8e76df77fb","previews":[]},"type":"conversation.message-add"}}
+      bad_message = {"conversation":"#{conversation_et.id}","id":"aeac8355-739b-4dfc-a119-891a52c6a8dc","from":"532af01e-1e24-4366-aacf-33b67d4ee376","data":{"content":"Hello World :)","nonce":"aeac8355-739b-4dfc-a119-891a52c6a8dc"},"type":"conversation.message-add"}
+      good_message = {"conversation":"#{conversation_et.id}","id":"5a8cd79a-82bb-49ca-a59e-9a8e76df77fb","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:33.389Z","data":{"content":"Fifth message","nonce":"5a8cd79a-82bb-49ca-a59e-9a8e76df77fb","previews":[]},"type":"conversation.message-add"}
       #@formatter:on
-      bad_message_key = "#{conversation_et.id}@#{bad_message.raw.from}@NaN"
-      good_message_key = "#{conversation_et.id}@#{good_message.raw.from}@#{new Date(good_message.raw.time).getTime()}"
+      bad_message_key = "#{conversation_et.id}@#{bad_message.from}@NaN"
+      good_message_key = "#{conversation_et.id}@#{good_message.from}@#{new Date(good_message.time).getTime()}"
 
       object_store = storage_service.OBJECT_STORE_CONVERSATION_EVENTS
 
diff --git a/test/unit_tests/conversation/ConversationServiceSpec.coffee b/test/unit_tests/conversation/ConversationServiceSpec.coffee
index 6d466a69b08..14d0e0db2c6 100644
--- a/test/unit_tests/conversation/ConversationServiceSpec.coffee
+++ b/test/unit_tests/conversation/ConversationServiceSpec.coffee
@@ -18,7 +18,7 @@
 
 # grunt test_init && grunt test_run:conversation/ConversationService
 
-describe 'Conversation Service', ->
+describe 'z.conversation.ConversationService', ->
   conversation_mapper = null
   server = null
 
@@ -75,18 +75,18 @@ describe 'Conversation Service', ->
     messages = [
       {
         key: "#{conversation_id}@#{sender_id}@1470317275182"
-        object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:55.182Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317275182,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:55.182Z","data":{"content":"First message","nonce":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","previews":[]},"type":"conversation.message-add"}}
+        object: {"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:55.182Z","data":{"content":"First message","nonce":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","previews":[]},"type":"conversation.message-add"}
       },
       {
         key: "#{conversation_id}@#{sender_id}@1470317278993"
-        object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317278993,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"4af67f76-09f9-4831-b3a4-9df877b8c29a","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","data":{"content":"Second message","nonce":"4af67f76-09f9-4831-b3a4-9df877b8c29a","previews":[]},"type":"conversation.message-add"}}
+        object: {"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"4af67f76-09f9-4831-b3a4-9df877b8c29a","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","data":{"content":"Second message","nonce":"4af67f76-09f9-4831-b3a4-9df877b8c29a","previews":[]},"type":"conversation.message-add"}
       }
     ]
     # @formatter:on
 
     beforeEach (done) ->
       Promise.all messages.map (message) ->
-        return conversation_service.storage_service.save storage_service.OBJECT_STORE_CONVERSATION_EVENTS, message.key, message.object
+        return storage_service.save storage_service.OBJECT_STORE_CONVERSATION_EVENTS, message.key, message.object
       .then done
       .catch done.fail
 
@@ -104,97 +104,84 @@ describe 'Conversation Service', ->
         done()
       .catch done.fail
 
-  describe 'update_message_timestamp_in_db', ->
+  describe 'update_message_in_db', ->
     # @formatter:off
-    messages = [
-      {
-        key: '35a9a89d-70dc-4d9e-88a2-4d8758458a6a@8b497692-7a38-4a5d-8287-e3d1006577d6@1470317278993'
-        object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317278993,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"4af67f76-09f9-4831-b3a4-9df877b8c29a","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","data":{"content":"Second message","nonce":"4af67f76-09f9-4831-b3a4-9df877b8c29a","previews":[]},"type":"conversation.message-add"}}
-      }
-    ]
+    event = {"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"4af67f76-09f9-4831-b3a4-9df877b8c29a","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","data":{"content":"Second message","nonce":"4af67f76-09f9-4831-b3a4-9df877b8c29a","previews":[]},"type":"conversation.message-add"}
     # @formatter:on
 
-    beforeEach (done) ->
-      Promise.all messages.map (message) ->
-        return conversation_service.storage_service.save storage_service.OBJECT_STORE_CONVERSATION_EVENTS, message.key, message.object
+    it 'updated event in the database', (done) ->
+      event.time = new Date(Date.now()).toISOString()
+      conversation_service.update_message_in_db event, {time: event.time}
       .then done
       .catch done.fail
 
-    it 'returns updated record', (done) ->
-      timestamp = Date.now()
-      time = new Date(timestamp).toISOString()
-      conversation_service.update_message_timestamp_in_db messages[0].key, timestamp
-      .then (record) =>
-        expect(record.mapped.time).toEqual time
-        expect(record.mapped.data.edited_time).toEqual messages[0].object.mapped.time
-        expect(record.meta.timestamp).toEqual timestamp
-        expect(record.raw.time).toEqual time
-        done()
-      .catch done.fail
-
-    it 'fails if no timestamp is specified', (done) ->
-      conversation_service.update_message_timestamp_in_db messages[0].key, undefined
+    it 'fails if changes are not specified', (done) ->
+      conversation_service.update_message_in_db event, undefined
       .then done.fail
       .catch (error) ->
-        expect((error)).toEqual jasmine.any(TypeError)
+        expect(error).toEqual jasmine.any z.conversation.ConversationError
+        expect(error.type).toBe z.conversation.ConversationError::TYPE.NO_CHANGES
         done()
 
   describe 'load_events_from_db', ->
-    it 'returns an information set about the loaded events even if no records are found', (done) ->
-      conversation_service.load_events_from_db 'invalid_id', 1466549621778, 30
-      .then (loaded_events) =>
-        [events, has_further_events] = loaded_events
+    conversation_id = '35a9a89d-70dc-4d9e-88a2-4d8758458a6a'
+    sender_id = '8b497692-7a38-4a5d-8287-e3d1006577d6'
+    messages = undefined
+
+    beforeEach (done) ->
+      messages = [0...10].map (index) ->
+        return {
+          key: "#{conversation_id}@#{sender_id}@#{index}"
+          object: {"conversation": conversation_id, "time": index}
+        }
+
+      Promise.all messages.map (message) ->
+        return storage_service.save storage_service.OBJECT_STORE_CONVERSATION_EVENTS, message.key, message.object
+      .then done
+      .catch done.fail
+
+    it 'doesnt load events for invalid conversation id', (done) ->
+      conversation_service.load_events_from_db 'invalid_id', 9, 30
+      .then (events) =>
         expect(events.length).toBe 0
-        expect(has_further_events).toBe false
         done()
 
-    it 'returns conversation events', (done) ->
-      conversation_id = '35a9a89d-70dc-4d9e-88a2-4d8758458a6a'
-      sender_id = '8b497692-7a38-4a5d-8287-e3d1006577d6'
+    it 'loads all events', (done) ->
+      conversation_service.load_events_from_db conversation_id
+      .then (events) =>
+        expect(events.length).toBe 10
+        done()
 
-      # @formatter:off
-      messages = [
-        {
-          key: "#{conversation_id}@#{sender_id}@1470317275182"
-          object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:55.182Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317275182,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:55.182Z","data":{"content":"First message","nonce":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","previews":[]},"type":"conversation.message-add"}}
-        },
-        {
-          key: "#{conversation_id}@#{sender_id}@1470317278993"
-          object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317278993,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"4af67f76-09f9-4831-b3a4-9df877b8c29a","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","data":{"content":"Second message","nonce":"4af67f76-09f9-4831-b3a4-9df877b8c29a","previews":[]},"type":"conversation.message-add"}}
-        },
-        {
-          key: "#{conversation_id}@#{sender_id}@1470317282495"
-          object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:02.495Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317282495,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"2e70c133-afe6-4265-bb4b-e71704529668","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:02.495Z","data":{"content":"Third message","nonce":"2e70c133-afe6-4265-bb4b-e71704529668","previews":[]},"type":"conversation.message-add"}}
-        },
-        {
-          key: "#{conversation_id}@#{sender_id}@1470317310019"
-          object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:30.019Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317310019,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"0880f7b9-b8f1-45e4-825e-fa120daa98b2","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:30.019Z","data":{"content":"Fourth message","nonce":"0880f7b9-b8f1-45e4-825e-fa120daa98b2","previews":[]},"type":"conversation.message-add"}}
-        },
-        {
-          key: "#{conversation_id}@#{sender_id}@1470317313389"
-          object: {"raw":{"from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:33.389Z","type":"conversation.otr-message-add","conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a"},"meta":{"timestamp":1470317313389,"version":1},"mapped":{"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"5a8cd79a-82bb-49ca-a59e-9a8e76df77fb","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:28:33.389Z","data":{"content":"Fifth message","nonce":"5a8cd79a-82bb-49ca-a59e-9a8e76df77fb","previews":[]},"type":"conversation.message-add"}}
-        }
-      ]
-      # @formatter:on
+    it 'loads all events with limit', (done) ->
+      conversation_service.load_events_from_db conversation_id, null, null, 5
+      .then (events) =>
+        expect(events.length).toBe 5
+        done()
+
+    it 'loads events with start timestamp', (done) ->
+      conversation_service.load_events_from_db conversation_id, 4
+      .then (events) =>
+        expect(events.length).toBe 4
+        expect(events[0].time).toBe 3
+        expect(events[1].time).toBe 2
+        expect(events[2].time).toBe 1
+        expect(events[3].time).toBe 0
+        done()
 
-      promises = []
-      for message in messages
-        promise = conversation_service.storage_service.save storage_service.OBJECT_STORE_CONVERSATION_EVENTS, message.key, message.object
-        promises.push promise
-
-      Promise.all promises
-      .then =>
-        limit = 4
-        conversation_service.load_events_from_db conversation_id, undefined, limit
-        .then (loaded_events) =>
-          [events, has_further_events] = loaded_events
-          expect(events.length).toBe limit
-          expect(has_further_events).toBe true
-          expect(events[0].meta.timestamp).toBe messages[messages.length - 1].object.meta.timestamp
-          expect(events[1].meta.timestamp).toBe messages[messages.length - 2].object.meta.timestamp
-          expect(events[2].meta.timestamp).toBe messages[messages.length - 3].object.meta.timestamp
-          expect(events[3].meta.timestamp).toBe messages[messages.length - limit].object.meta.timestamp
-          done()
+    it 'loads events with start and end timestamp', (done) ->
+      conversation_service.load_events_from_db conversation_id, 8, 6
+      .then (events) =>
+        expect(events.length).toBe 1
+        expect(events[0].time).toBe 7
+        done()
+
+    it 'loads events with start and end timestamp', (done) ->
+      conversation_service.load_events_from_db conversation_id, 8, 1, 2
+      .then (events) =>
+        expect(events.length).toBe 2
+        expect(events[0].time).toBe 7
+        expect(events[1].time).toBe 6
+        done()
 
   describe 'save_conversation_in_db', ->
     it 'saves a conversation', (done) ->
@@ -206,3 +193,52 @@ describe 'Conversation Service', ->
       .then (conversation_record) =>
         expect(conversation_record.name()).toBe conversation_payload.name
         done()
+
+  describe 'delete_message_with_key_from_db', ->
+
+    conversation_id = '35a9a89d-70dc-4d9e-88a2-4d8758458a6a'
+    sender_id = '8b497692-7a38-4a5d-8287-e3d1006577d6'
+
+    # @formatter:off
+    messages = [
+      {
+        key: "#{conversation_id}@#{sender_id}@1470317275182"
+        object: {"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:55.182Z","data":{"content":"First message","nonce":"68a28ab1-d7f8-4014-8b52-5e99a05ea3b1","previews":[]},"type":"conversation.message-add"}
+      },
+      {
+        key: "#{conversation_id}@#{sender_id}@1470317278993"
+        object: {"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"4af67f76-09f9-4831-b3a4-9df877b8c29a","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","data":{"content":"Second message","nonce":"4af67f76-09f9-4831-b3a4-9df877b8c29a","previews":[]},"type":"conversation.message-add"}
+      },
+
+      {
+        key: "#{conversation_id}@#{sender_id}@1470317278994"
+        object: {"conversation":"35a9a89d-70dc-4d9e-88a2-4d8758458a6a","id":"4af67f76-09f9-4831-b3a4-9df877b8c29a","from":"8b497692-7a38-4a5d-8287-e3d1006577d6","time":"2016-08-04T13:27:58.993Z","data":{"content":"Second message (Duplicate)","nonce":"4af67f76-09f9-4831-b3a4-9df877b8c29a","previews":[]},"type":"conversation.message-add"}
+      }
+    ]
+    # @formatter:on
+
+    beforeEach (done) ->
+      Promise.all messages.map (message) ->
+        return storage_service.save storage_service.OBJECT_STORE_CONVERSATION_EVENTS, message.key, message.object
+      .then done
+      .catch done.fail
+
+    it 'deletes message with the given key', (done) ->
+      conversation_service.delete_message_with_key_from_db conversation_id, messages[1].key
+      .then ->
+        conversation_service.load_events_from_db conversation_id
+      .then (events) ->
+        expect(events.length).toBe 2
+        for event in events
+          expect(event.data.content).not.toBe messages[1].object.data.content
+        done()
+      .catch done.fail
+
+    it 'does not delete if event if key is wrong', (done) ->
+      conversation_service.delete_message_with_key_from_db conversation_id, 'wrongKey'
+      .then ->
+        conversation_service.load_events_from_db conversation_id
+      .then (events) ->
+        expect(events.length).toBe 3
+        done()
+      .catch done.fail
diff --git a/test/unit_tests/cryptography/CryptographyMapperSpec.coffee b/test/unit_tests/cryptography/CryptographyMapperSpec.coffee
index c772e477fbe..04043f20437 100644
--- a/test/unit_tests/cryptography/CryptographyMapperSpec.coffee
+++ b/test/unit_tests/cryptography/CryptographyMapperSpec.coffee
@@ -51,7 +51,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.ASSET_META
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.ASSET_META
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -74,7 +74,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.ASSET_META
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.ASSET_META
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -102,7 +102,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.ASSET_UPLOAD_COMPLETE
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.ASSET_UPLOAD_COMPLETE
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -121,7 +121,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.ASSET_UPLOAD_FAILED
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.ASSET_UPLOAD_FAILED
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -140,7 +140,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.ASSET_UPLOAD_FAILED
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.ASSET_UPLOAD_FAILED
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -170,7 +170,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.ASSET_PREVIEW
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.ASSET_PREVIEW
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -208,7 +208,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.MESSAGE_HIDDEN
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.MESSAGE_HIDDEN
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -226,7 +226,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.MESSAGE_DELETE
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.MESSAGE_DELETE
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -327,6 +327,24 @@ describe 'z.cryptography.CryptographyMapper', ->
         done()
       .catch done.fail
 
+    it 'resolves with a mapped reaction message', (done) ->
+      message_id = z.util.create_random_uuid()
+      generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
+      generic_message.set 'reaction', new z.proto.Reaction '💖', message_id
+
+      mapper.map_generic_message generic_message, event
+      .then (event_json) ->
+        expect(_.isObject event_json).toBeTruthy()
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.REACTION
+        expect(event_json.conversation).toBe event.conversation
+        expect(event_json.from).toBe event.from
+        expect(event_json.time).toBe event.time
+        expect(event_json.id).toBe generic_message.message_id
+        expect(event_json.data.message_id).toBe message_id
+        expect(event_json.data.reaction).toBe '💖'
+        done()
+      .catch done.fail
+
     it 'resolves with a mapped text message', (done) ->
       generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
       generic_message.set 'text', new z.proto.Text 'Unit test'
@@ -349,12 +367,12 @@ describe 'z.cryptography.CryptographyMapper', ->
       .then done.fail
       .catch (error) ->
         expect(error instanceof z.cryptography.CryptographyError).toBeTruthy()
-        expect(error.type).toBe z.cryptography.CryptographyError::TYPE.MISSING_MESSAGE
+        expect(error.type).toBe z.cryptography.CryptographyError::TYPE.NO_GENERIC_MESSAGE
         done()
 
     it 'rejects with an error for an unhandled generic message type', (done) ->
       generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
-      generic_message.set 'liking', z.proto.LikeAction.LIKE
+      generic_message.set 'calling', new z.proto.Calling 'Test'
 
       mapper.map_generic_message generic_message, {id: 'ABC'}
       .then done.fail
@@ -421,7 +439,7 @@ describe 'z.cryptography.CryptographyMapper', ->
       mapper.map_generic_message generic_message, event
       .then (event_json) ->
         expect(_.isObject event_json).toBeTruthy()
-        expect(event_json.type).toBe z.event.Backend.CONVERSATION.LOCATION
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.LOCATION
         expect(event_json.conversation).toBe event.conversation
         expect(event_json.from).toBe event.from
         expect(event_json.time).toBe event.time
@@ -433,3 +451,20 @@ describe 'z.cryptography.CryptographyMapper', ->
         expect(event_json.data.nonce).toBe generic_message.message_id
         done()
       .catch done.fail
+
+    it 'resolves with a mapped reaction message', (done) ->
+      generic_message = new z.proto.GenericMessage z.util.create_random_uuid()
+      generic_message.set 'reaction', new z.proto.Reaction z.message.ReactionType.LIKE, generic_message.message_id
+
+      mapper.map_generic_message generic_message, event
+      .then (event_json) ->
+        expect(_.isObject event_json).toBeTruthy()
+        expect(event_json.type).toBe z.event.Client.CONVERSATION.REACTION
+        expect(event_json.conversation).toBe event.conversation
+        expect(event_json.from).toBe event.from
+        expect(event_json.time).toBe event.time
+        expect(event_json.id).toBe generic_message.message_id
+        expect(event_json.data.message_id).toBe generic_message.message_id
+        expect(event_json.data.reaction).toBe z.message.ReactionType.LIKE
+        done()
+      .catch done.fail
diff --git a/test/unit_tests/entity/ConversationSpec.coffee b/test/unit_tests/entity/ConversationSpec.coffee
index d3403b176f0..258c359496e 100644
--- a/test/unit_tests/entity/ConversationSpec.coffee
+++ b/test/unit_tests/entity/ConversationSpec.coffee
@@ -284,7 +284,7 @@ describe 'Conversation', ->
 
     it 'detects duplicate messages', ->
       content = z.message.SuperType.CONTENT
-      asset_meta = z.event.Backend.CONVERSATION.ASSET_META
+      asset_meta = z.event.Client.CONVERSATION.ASSET_META
 
       message1.super_type = content
       message1.type = asset_meta
@@ -505,14 +505,14 @@ describe 'Conversation', ->
       older_message_et.timestamp = older_timestamp
       older_message_et.id = z.util.create_random_uuid()
       older_message_et.nonce = z.util.create_random_uuid()
-      older_message_et.type = z.event.Backend.CONVERSATION.ASSET_META
+      older_message_et.type = z.event.Client.CONVERSATION.ASSET_META
       older_message_et.add_asset asset_et
 
       newer_message_et = new z.entity.ContentMessage()
       newer_message_et.timestamp = newer_timestamp
       newer_message_et.id = older_message_et.id
       newer_message_et.nonce = older_message_et.nonce
-      newer_message_et.type = z.event.Backend.CONVERSATION.ASSET_META
+      newer_message_et.type = z.event.Client.CONVERSATION.ASSET_META
       newer_message_et.add_asset asset_et
 
       conversation_et._check_for_duplicate_nonce older_message_et, newer_message_et
diff --git a/test/unit_tests/event/EventRepositorySpec.coffee b/test/unit_tests/event/EventRepositorySpec.coffee
index a45ea33aa14..975b1d4cbdd 100644
--- a/test/unit_tests/event/EventRepositorySpec.coffee
+++ b/test/unit_tests/event/EventRepositorySpec.coffee
@@ -51,7 +51,7 @@ describe 'Event Repository', ->
         if last_notification_id
           Promise.resolve last_notification_id
         else
-          Promise.reject new z.event.EventError 'ID not found in storage', z.event.EventError::TYPE.DATABASE_NOT_FOUND
+          Promise.reject new z.event.EventError z.event.EventError::TYPE.NO_LAST_ID
 
       notification_service.save_last_notification_id_to_db = ->
         Promise.resolve z.event.NotificationService::PRIMARY_KEY_LAST_NOTIFICATION
@@ -72,7 +72,7 @@ describe 'Event Repository', ->
       spyOn(notification_service, 'get_last_notification_id_from_db').and.callThrough()
 
     it 'should skip fetching notifications if last notification ID not found in storage', (done) ->
-      event_repository.connect()
+      event_repository.connect_web_socket()
       event_repository.update_from_notification_stream()
       .then ->
         expect(notification_service.get_last_notification_id_from_db).toHaveBeenCalled()
@@ -82,18 +82,18 @@ describe 'Event Repository', ->
 
     it 'should buffer notifications when notification stream is not processed', ->
       last_notification_id = z.util.create_random_uuid()
-      event_repository.connect()
+      event_repository.connect_web_socket()
       websocket_service_mock.publish {id: z.util.create_random_uuid(), payload: []}
       expect(event_repository._buffer_web_socket_notification).toHaveBeenCalled()
       expect(event_repository._handle_notification).not.toHaveBeenCalled()
-      expect(event_repository.can_handle_web_socket()).toBeFalsy()
+      expect(event_repository.notification_handling_state()).toBe z.event.NotificationHandlingState.STREAM
       expect(event_repository.web_socket_buffer.length).toBe 1
 
     it 'should handle buffered notifications after notifications stream was processed', (done) ->
       last_notification_id = z.util.create_random_uuid()
       last_published_notification_id = z.util.create_random_uuid()
       event_repository.last_notification_id last_notification_id
-      event_repository.connect()
+      event_repository.connect_web_socket()
       websocket_service_mock.publish {id: z.util.create_random_uuid(), payload: []}
 
       websocket_service_mock.publish {id: last_published_notification_id, payload: []}
@@ -102,151 +102,150 @@ describe 'Event Repository', ->
         expect(event_repository._handle_buffered_notifications).toHaveBeenCalled()
         expect(event_repository.web_socket_buffer.length).toBe 0
         expect(event_repository.last_notification_id()).toBe last_published_notification_id
-        expect(event_repository.can_handle_web_socket()).toBeTruthy()
+        expect(event_repository.notification_handling_state()).toBe z.event.NotificationHandlingState.WEB_SOCKET
         done()
       .catch done.fail
 
   describe '_handle_event', ->
     beforeEach ->
-      spyOn(cryptography_repository, 'save_encrypted_event').and.returnValue Promise.resolve(mapped: 'dummy content')
+      event_repository.notification_handling_state z.event.NotificationHandlingState.WEB_SOCKET
+      spyOn(cryptography_repository, 'save_encrypted_event').and.returnValue Promise.resolve({data: 'dummy content'})
+      spyOn(cryptography_repository, 'save_unencrypted_event').and.returnValue Promise.resolve({data: 'dummy content'})
       spyOn(event_repository, '_distribute_event')
 
     it 'should not save but distribute user events', (done) ->
-      event_repository._handle_event {type: z.event.Backend.USER.UPDATE}, z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
+      event_repository._handle_event {type: z.event.Backend.USER.UPDATE}, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
       .then ->
         expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).not.toHaveBeenCalled()
         expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
 
     it 'should not save but distribute call events', (done) ->
-      event_repository._handle_event {type: z.event.Backend.CALL.FLOW_ACTIVE}, z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
+      event_repository._handle_event {type: z.event.Backend.CALL.FLOW_ACTIVE}, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
       .then ->
         expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).not.toHaveBeenCalled()
         expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
 
     it 'should not save but distribute conversation.create event', (done) ->
-      event_repository._handle_event {type: z.event.Backend.CONVERSATION.CREATE}, z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
+      event_repository._handle_event {type: z.event.Backend.CONVERSATION.CREATE}, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
       .then ->
         expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).not.toHaveBeenCalled()
         expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
 
-    it 'shouldn\'t save and distribute "conversation.message-add" events', (done) ->
+    it 'skips outdated "conversation.message-add" events arriving', (done) ->
       # @formatter:off
-      event = {"conversation":"9fe8b359-b9e0-4624-b63c-71747664e4fa","time":"2016-08-12T10:40:58.769Z","data":{"content":"unencrypted","nonce":"9f239249-3648-4a6c-a5f6-a3c8f902a919"},"from":"062418ea-9b93-4d93-b59b-11aba3f702d8","id":"754.800122000b3f0470","type":"conversation.message-add"}
+      event = {"conversation":"9fe8b359-b9e0-4624-b63c-71747664e4fa","time":"2016-08-05T16:18:41.820Z","data":{"content":"Hello","nonce":"1cea64c5-afbe-4c9d-b7d0-c49aa3b0a53d"},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"74f.800122000b2d7182","type":"conversation.message-add"}
       # @formatter:on
 
-      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
-      .catch (error) ->
-        expect(error.message).toBe z.event.EventError::TYPE.OUTDATED_SCHEMA
-        done()
-
-    it 'skips outdated "conversation.message-add" events arriving via WebSocket', (done) ->
-      # @formatter:off
-      notification = {"payload":[{"conversation":"9fe8b359-b9e0-4624-b63c-71747664e4fa","time":"2016-08-05T16:18:41.820Z","data":{"content":"  Hello","nonce":"1cea64c5-afbe-4c9d-b7d0-c49aa3b0a53d"},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"74f.800122000b2d7182","type":"conversation.message-add"}],"transient":false,"id":"46569440-5b28-11e6-bfff-22000a520a63"}
-      # @formatter:on
-
-      event = notification.payload[0]
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
-
-      event_repository._handle_event event, source
-      .catch (error) ->
-        expect(error.message).toBe z.event.EventError::TYPE.OUTDATED_SCHEMA
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then (result) ->
+        expect(result).toBeTruthy()
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).not.toHaveBeenCalled()
+        expect(event_repository._distribute_event).not.toHaveBeenCalled()
         done()
+      .catch done.fail
 
     it 'skips outdated "conversation.asset-add" events', (done) ->
       # @formatter:off
       event = {"data":{"data":"/9j/4AAQSkZJRgABAQAAAQABAAD/.../Z","content_type":"image/jpeg","id":"01c86ab7-4d38-4a4e-8e7e-e6d73a3c2b94","content_length":1218,"info":{"original_width":1094,"public":true,"width":49,"correlation_id":"48aa1bd4-fbb1-4cdc-bbbc-7160dc4d032e","original_height":1919,"tag":"preview","nonce":"48aa1bd4-fbb1-4cdc-bbbc-7160dc4d032e","height":86}},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","time":"2015-12-18T11:15:00.201Z","id":"ae8.800122000b259e4e","type":"conversation.asset-add","conversation":"5aeafc6d-2a2d-4105-bc87-41cc8b72774a"}
       # @formatter:on
 
-      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
-      .catch (error) ->
-        expect(error.message).toBe z.event.EventError::TYPE.OUTDATED_SCHEMA
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then (result) ->
+        expect(result).toBeTruthy()
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).not.toHaveBeenCalled()
+        expect(event_repository._distribute_event).not.toHaveBeenCalled()
         done()
+      .catch done.fail
 
     it 'skips outdated "conversation.knock" events', (done) ->
       # @formatter:off
       event = {"data":{"nonce":"33a16765-2b23-42a1-b1cc-414d1baa9095"},"from":"d794bf14-96a0-43e9-be95-ae761d1acb4e","time":"2015-12-21T10:14:59.661Z","id":"a2b.800122000ad94450","type":"conversation.knock","conversation":"872eaa34-9673-44af-abaa-e1b6979a7cff"}
       # @formatter:on
 
-      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
-      .catch (error) ->
-        expect(error.message).toBe z.event.EventError::TYPE.OUTDATED_SCHEMA
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then (result) ->
+        expect(result).toBeTruthy()
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).not.toHaveBeenCalled()
+        expect(event_repository._distribute_event).not.toHaveBeenCalled()
         done()
+      .catch done.fail
 
     it 'skips outdated events arriving via notification stream', (done) ->
+      event_repository.notification_handling_state z.event.NotificationHandlingState.STREAM
       # @formatter:off
-      notification = {"payload":[{"conversation":"9fe8b359-b9e0-4624-b63c-71747664e4fa","time":"2016-08-05T16:18:41.820Z","data":{"content":"  Hello","nonce":"1cea64c5-afbe-4c9d-b7d0-c49aa3b0a53d"},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"74f.800122000b2d7182","type":"conversation.message-add"}],"transient":false,"id":"46569440-5b28-11e6-bfff-22000a520a63"}
-      # @formatter:on
-      event = notification.payload[0]
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.STREAM
-
-      event_repository._handle_event event, source
-      .catch (error) ->
-        expect(error.message).toBe z.event.EventError::TYPE.OUTDATED_SCHEMA
-        done()
-
-    it 'skips outdated events which get injected', (done) ->
-      # @formatter:off
-      notification = {"payload":[{"conversation":"9fe8b359-b9e0-4624-b63c-71747664e4fa","time":"2016-08-05T16:18:41.820Z","data":{"content":"  Hello","nonce":"1cea64c5-afbe-4c9d-b7d0-c49aa3b0a53d"},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"74f.800122000b2d7182","type":"conversation.message-add"}],"transient":false,"id":"46569440-5b28-11e6-bfff-22000a520a63"}
+      event = {"conversation":"9fe8b359-b9e0-4624-b63c-71747664e4fa","time":"2016-08-05T16:18:41.820Z","data":{"content":"Hello","nonce":"1cea64c5-afbe-4c9d-b7d0-c49aa3b0a53d"},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"74f.800122000b2d7182","type":"conversation.message-add"}
       # @formatter:on
-      event = notification.payload[0]
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.INJECTION
 
-      event_repository._handle_event event, source
-      .catch (error) ->
-        expect(error.message).toBe z.event.EventError::TYPE.OUTDATED_SCHEMA
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.STREAM
+      .then (result) ->
+        expect(result).toBeTruthy()
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).not.toHaveBeenCalled()
+        expect(event_repository._distribute_event).not.toHaveBeenCalled()
         done()
+      .catch done.fail
 
-    it 'accepts plain conversation rename events', (done) ->
+    it 'accepts conversation.rename events', (done) ->
       # @formatter:off
       event = {"conversation":"64dcb45f-bf8d-4eac-a263-649a60d69305","time":"2016-08-09T11:57:37.498Z","data":{"name":"Renamed"},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"7.800122000b2f7cca","type":"conversation.rename"}
       # @formatter:on
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
 
-      event_repository._handle_event event, source
-      .then (record) ->
-        expect(record.raw.type).toBe z.event.Backend.CONVERSATION.RENAME
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then ->
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).toHaveBeenCalled()
+        expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
 
-    it 'accepts plain member join events', (done) ->
+    it 'accepts conversation.member-join events', (done) ->
       # @formatter:off
       event = {"conversation":"64dcb45f-bf8d-4eac-a263-649a60d69305","time":"2016-08-09T12:01:14.688Z","data":{"user_ids":["e47bfafa-03dc-43ed-aadb-ad6c4d9f3d86"]},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"8.800122000b2f7d20","type":"conversation.member-join"}
       # @formatter:on
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
 
-      event_repository._handle_event event, source
-      .then (record) ->
-        expect(record.raw.type).toBe z.event.Backend.CONVERSATION.MEMBER_JOIN
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then ->
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).toHaveBeenCalled()
+        expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
 
-    it 'accepts plain member leave events', (done) ->
+    it 'accepts conversation.member-leave events', (done) ->
       # @formatter:off
       event = {"conversation":"64dcb45f-bf8d-4eac-a263-649a60d69305","time":"2016-08-09T12:01:56.363Z","data":{"user_ids":["e47bfafa-03dc-43ed-aadb-ad6c4d9f3d86"]},"from":"532af01e-1e24-4366-aacf-33b67d4ee376","id":"9.800122000b3d69bc","type":"conversation.member-leave"}
       # @formatter:on
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
 
-      event_repository._handle_event event, source
-      .then (record) ->
-        expect(record.raw.type).toBe z.event.Backend.CONVERSATION.MEMBER_LEAVE
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then ->
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).toHaveBeenCalled()
+        expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
 
-    it 'accepts plain missed calls events', (done) ->
+    it 'accepts conversation.voice-channel-deactivate (missed call) events', (done) ->
       # @formatter:off
       event = {"conversation":"64dcb45f-bf8d-4eac-a263-649a60d69305","time":"2016-08-09T12:09:28.294Z","data":{"reason":"missed"},"from":"0410795a-58dc-40d8-b216-cbc2360be21a","id":"16.800122000b3d4ade","type":"conversation.voice-channel-deactivate"}
       # @formatter:on
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
 
-      event_repository._handle_event event, source
-      .then (record) ->
-        expect(record.raw.type).toBe z.event.Backend.CONVERSATION.VOICE_CHANNEL_DEACTIVATE
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then ->
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).toHaveBeenCalled()
+        expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
 
@@ -254,10 +253,11 @@ describe 'Event Repository', ->
       # @formatter:off
       event = {"conversation":"7f0939c8-dbd9-48f5-839e-b0ebcfffec8c","id":"f518d6ff-19d3-48a0-b0c1-cc71c6e81136","type":"conversation.unable-to-decrypt","from":"532af01e-1e24-4366-aacf-33b67d4ee376","time":"2016-08-09T12:58:49.485Z","error":"Offset is outside the bounds of the DataView (17cd13b4b2a3a98)","error_code":"1778 (17cd13b4b2a3a98)"}
       # @formatter:on
-      source = z.event.EventRepository::NOTIFICATION_SOURCE.SOCKET
 
-      event_repository._handle_event event, source
-      .then (record) ->
-        expect(record.raw.type).toBe z.event.Client.CONVERSATION.UNABLE_TO_DECRYPT
+      event_repository._handle_event event, z.event.EventRepository::NOTIFICATION_SOURCE.WEB_SOCKET
+      .then ->
+        expect(cryptography_repository.save_encrypted_event).not.toHaveBeenCalled()
+        expect(cryptography_repository.save_unencrypted_event).toHaveBeenCalled()
+        expect(event_repository._distribute_event).toHaveBeenCalled()
         done()
       .catch done.fail
diff --git a/test/unit_tests/storage/StorageRepositorySpec.coffee b/test/unit_tests/storage/StorageRepositorySpec.coffee
index 2fd2f7aee45..e71e61fcd1c 100644
--- a/test/unit_tests/storage/StorageRepositorySpec.coffee
+++ b/test/unit_tests/storage/StorageRepositorySpec.coffee
@@ -27,37 +27,6 @@ describe 'z.storage.StorageRepository', ->
   beforeEach ->
     storage_repository.clear_all_stores()
 
-  describe 'construct_primary_key', ->
-    it 'constructs primary keys', ->
-      conversation_id = '35d8767e-83c9-4e9a-a5ee-32ba7de706f2'
-      sender_id = '532af01e-1e24-4366-aacf-33b67d4ee376'
-      time = '2016-07-09T19:10:55.076Z'
-
-      actual = storage_repository.construct_primary_key conversation_id, sender_id, time
-      expected = "#{conversation_id}@#{sender_id}@1468091455076"
-
-      expect(actual).toBe expected
-
-    it 'works with timestamps', ->
-      conversation_id = '35d8767e-83c9-4e9a-a5ee-32ba7de706f2'
-      sender_id = '532af01e-1e24-4366-aacf-33b67d4ee376'
-      timestamp = 1468091455076
-
-      actual = storage_repository.construct_primary_key conversation_id, sender_id, timestamp
-      expected = "#{conversation_id}@#{sender_id}@#{timestamp}"
-
-      expect(actual).toBe expected
-
-    it 'throws an error on missing timestamps', ->
-      expect ->
-        storage_repository.construct_primary_key 'A', 'A'
-      .toThrowError z.storage.StorageError, z.storage.StorageError::TYPE.INVALID_TIMESTAMP
-
-    it 'throws an error on invalid timestamps', ->
-      expect ->
-        storage_repository.construct_primary_key 'A', 'A', 'A'
-      .toThrowError z.storage.StorageError, z.storage.StorageError::TYPE.INVALID_TIMESTAMP
-
   describe 'save_value',  ->
     it 'persists primitive values in an object format', (done)->
       primary_key = 'test_key'
@@ -68,4 +37,3 @@ describe 'z.storage.StorageRepository', ->
         expect(storage_key).toBe primary_key
         done()
       .catch done.fail
-
diff --git a/test/unit_tests/storage/StorageServiceSpec.coffee b/test/unit_tests/storage/StorageServiceSpec.coffee
new file mode 100644
index 00000000000..3cf922ef917
--- /dev/null
+++ b/test/unit_tests/storage/StorageServiceSpec.coffee
@@ -0,0 +1,62 @@
+#
+# Wire
+# Copyright (C) 2016 Wire Swiss GmbH
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+#
+
+# grunt test_init && grunt test_run:storage/StorageService
+
+describe 'z.storage.StorageService', ->
+  describe 'construct_primary_key', ->
+    event = undefined
+    expected_key = undefined
+
+    beforeEach ->
+      event =
+        conversation: '35d8767e-83c9-4e9a-a5ee-32ba7de706f2'
+        from: '532af01e-1e24-4366-aacf-33b67d4ee376'
+        time: '2016-07-09T19:10:55.076Z'
+      expected_key = "#{event.conversation}@#{event.from}@1468091455076"
+
+    it 'constructs primary keys', ->
+      actual = z.storage.StorageService.construct_primary_key event
+
+      expect(actual).toBe expected_key
+
+    it 'works with timestamps', ->
+      event.time = 1468091455076
+      actual = z.storage.StorageService.construct_primary_key event
+
+      expect(actual).toBe expected_key
+
+    it 'throws an error on missing conversation ID', ->
+      event.conversation = null
+      function_call = -> z.storage.StorageService.construct_primary_key event
+      expect(function_call).toThrowError z.storage.StorageError, 'Missing conversation ID'
+
+    it 'throws an error on missing user ID', ->
+      event.from = null
+      function_call = -> z.storage.StorageService.construct_primary_key event
+      expect(function_call).toThrowError z.storage.StorageError, 'Missing sender ID'
+
+    it 'throws an error on missing time', ->
+      event.time = null
+      function_call = -> z.storage.StorageService.construct_primary_key event
+      expect(function_call).toThrowError z.storage.StorageError, 'Missing time'
+
+    it 'throws an error on invalid timestamps', ->
+      event.time = 'A'
+      function_call = -> z.storage.StorageService.construct_primary_key event
+      expect(function_call).toThrowError z.storage.StorageError, 'Invalid timestamp'
diff --git a/test/unit_tests/system_notification/SystemNotificationRepositorySpec.coffee b/test/unit_tests/system_notification/SystemNotificationRepositorySpec.coffee
index a1e05eaed5d..b381b3f7abb 100644
--- a/test/unit_tests/system_notification/SystemNotificationRepositorySpec.coffee
+++ b/test/unit_tests/system_notification/SystemNotificationRepositorySpec.coffee
@@ -30,7 +30,7 @@ describe 'z.SystemNotification.SystemNotificationRepository', ->
   beforeEach (done) ->
     test_factory.exposeSystemNotificationActors()
     .then ->
-      amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, false
+      amplify.publish z.event.WebApp.EVENT.NOTIFICATION_HANDLING_STATE, z.event.NotificationHandlingState.WEB_SOCKET
 
       # Create entities
       user_et = user_repository.user_mapper.map_user_from_object payload.users.get.one[0]
diff --git a/test/unit_tests/tracking/EventTrackingRepositorySpec.coffee b/test/unit_tests/tracking/EventTrackingRepositorySpec.coffee
index a14ca3ba166..fbd5627d3e6 100644
--- a/test/unit_tests/tracking/EventTrackingRepositorySpec.coffee
+++ b/test/unit_tests/tracking/EventTrackingRepositorySpec.coffee
@@ -170,10 +170,9 @@ describe 'z.tracking.EventTrackingRepository', ->
       Promise.reject new Error 'Unit test error'
 
     it 'handles a Promise rejected with a String that is uncaught', (done) ->
-      window.onerror = (error_message, file_name, line_number, column_number, error) ->
+      window.onerror = (error_message, file_name) ->
         expect(error_message).toBe error_description
-        expect(error).toBe error_description
-        expect(error.message).toBeUndefined()
+        expect(file_name).toBeNull()
         done()
 
       Promise.reject 'Unit test error'
diff --git a/test/unit_tests/util/UtilSpec.coffee b/test/unit_tests/util/UtilSpec.coffee
index 47f16b26562..a3329236e5a 100644
--- a/test/unit_tests/util/UtilSpec.coffee
+++ b/test/unit_tests/util/UtilSpec.coffee
@@ -18,56 +18,53 @@
 
 # grunt test_init && grunt test_run:util/Util
 
-###############################################################################
-# z.util.render_message
-###############################################################################
 describe 'z.util.render_message', ->
   it 'renders a normal link', ->
     actual = z.util.render_message 'Check this: http://www.wire.com/'
-    expected = 'Check this: <a href="http://www.wire.com/" target="_blank" rel="nofollow">http://www.wire.com/</a>'
+    expected = 'Check this: <a href="http://www.wire.com/" target="_blank" rel="nofollow noopener noreferrer">http://www.wire.com/</a>'
     expect(actual).toBe expected
 
   it 'renders a normal link without protocol', ->
     actual = z.util.render_message 'Check this: wire.com/about/'
-    expected = 'Check this: <a href="http://wire.com/about/" target="_blank" rel="nofollow">wire.com/about/</a>'
+    expected = 'Check this: <a href="http://wire.com/about/" target="_blank" rel="nofollow noopener noreferrer">wire.com/about/</a>'
     expect(actual).toBe expected
 
   it 'renders complicated image links', ->
     link = 'http://static.err.ee/gridfs/95E91BE0D28DF7236BC00EE349284A451C05949C2D04E7857BC686E4394F1585.jpg?&crop=(0,27,848,506.0960451977401)&cropxunits=848&cropyunits=595&format=jpg&quality=90&width=752&maxheight=42'
     actual = z.util.render_message link
-    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow\">#{link}</a>"
+    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">#{link}</a>"
     expect(actual).toBe expected
 
   it 'renders URLs with underscores', ->
     link = 'http://en.wikipedia.org/wiki/Stormtrooper_(Star_Wars)'
     text = "Stormtroopers: #{link} !!!"
     actual = z.util.render_message text
-    expected = "Stormtroopers: <a href=\"#{link}\" target=\"_blank\" rel=\"nofollow\">#{link}</a> !!!"
+    expected = "Stormtroopers: <a href=\"#{link}\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">#{link}</a> !!!"
     expect(actual).toBe expected
 
   it 'renders links with multiple underscores', ->
     link = 'https://www.nike.com/events-registration/event?id=6245&languageLocale=de_de&cp=EUNS_KW_DE_&s_kwcid=AL!2799!3!46005237943!b!!g!!womens%20running'
     actual = z.util.render_message link
-    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow\">#{link}</a>"
+    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">#{link}</a>"
     expect(actual).toBe expected
 
   it 'renders URLs without a trailing slash', ->
     link = 'http://www.underscore.com'
     text = "e.g. #{link}."
     actual = z.util.render_message text
-    expected = "e.g. <a href=\"#{link}\" target=\"_blank\" rel=\"nofollow\">#{link}</a>."
+    expected = "e.g. <a href=\"#{link}\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">#{link}</a>."
     expect(actual).toBe expected
 
   it 'renders localhost links', ->
     link = 'http://localhost:8888/'
     actual = z.util.render_message link
-    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow\">#{link}</a>"
+    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">#{link}</a>"
     expect(actual).toBe expected
 
   it 'renders links with IP addresses', ->
     link = 'http://192.168.10.44:8080//job/webapp_atomic_test/4290/cucumber-html-reports'
     actual = z.util.render_message link
-    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow\">#{link}</a>"
+    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">#{link}</a>"
     expect(actual).toBe expected
 
   it 'escapes links when they are posted as plain HTML', ->
@@ -114,19 +111,18 @@ describe 'z.util.render_message', ->
     actual = z.util.render_message text
     expect(actual).toBe text
 
-###############################################################################
-# z.util.encode_base64_md5_array_buffer_view
-###############################################################################
+  xit 'renders URLs with @-signs correctly', ->
+    link = 'https://www.mail-archive.com/debian-bugs-dist@lists.debian.org/msg1448956.html'
+    actual = z.util.render_message link
+    expected = "<a href=\"#{link}\" target=\"_blank\" rel=\"nofollow noopener noreferrer\">#{link}</a>"
+    expect(actual).toBe expected
+
 describe 'z.util.encode_base64_md5_array_buffer_view', ->
   it 'can convert typed array to base64', ->
     actual = z.util.encode_base64_md5_array_buffer_view(new Uint8Array([8,8]))
     expected = 'w+7NCDwPSCf1JgWbA7deTA=='
     expect(actual).toBe expected
 
-
-###############################################################################
-# z.util.encode_base64
-###############################################################################
 describe 'z.util.encode_base64', ->
   it 'encodes text', ->
     actual = z.util.encode_base64 'Hello, world!'
@@ -138,10 +134,6 @@ describe 'z.util.encode_base64', ->
     expected = 'SGVsbG8sIHdvcmxkIUAjJCVeJiooKV8re31bXXw8PiwuPy9+YCI='
     expect(actual).toBe expected
 
-
-###############################################################################
-# z.util.encode_base64_sha256
-###############################################################################
 describe 'z.util.encode_base64_sha256', ->
   it 'encodes Base64 and SHA-256 empty string', ->
     actual = z.util.encode_sha256_base64 ''
@@ -158,22 +150,13 @@ describe 'z.util.encode_base64_sha256', ->
     expected = 'lt/heVPfGQB07sONclI2TZBZHuIMH86noUEWEbahMw4='
     expect(actual).toBe expected
 
-
-###############################################################################
-# z.util.base64_to_blob
-###############################################################################
 describe 'z.util.base64_to_blob', ->
-
   it 'encodes Base64 data URI to blob', ->
     base64 = z.util.array_to_base64 new Uint8Array [1, 2, 3]
     data_uri = "data:application/octet-binary;base64,#{base64}"
     blob = z.util.base64_to_blob data_uri
     expect(blob.type).toBe 'application/octet-binary'
 
-
-###############################################################################
-# z.util.create_random_uuid
-###############################################################################
 describe 'z.util.create_random_uuid', ->
   it 'has the right length', ->
     actual = z.util.create_random_uuid().length
@@ -190,30 +173,18 @@ describe 'z.util.create_random_uuid', ->
     expected = true
     expect(actual).toBe expected
 
-
-###############################################################################
-# z.util.bytes_to_uuid
-###############################################################################
 describe 'z.util.bytes_to_uuid', ->
   it 'creates uuid from byte array', ->
     expected = '1692b76b-d66b-4688-a099-71512ec1f51e'
     actual = z.util.bytes_to_uuid [22, 146, 183, 107, 214, 107, 70, 136, 160, 153, 113, 81, 46, 193, 245, 30]
     expect(actual).toBe expected
 
-
-###############################################################################
-# z.util.uuid_to_bytes
-###############################################################################
 describe 'z.util.uuid_to_bytes', ->
   it 'creates byte array from uuid', ->
     expected = [22, 146, 183, 107, 214, 107, 70, 136, 160, 153, 113, 81, 46, 193, 245, 30]
     actual = z.util.uuid_to_bytes '1692b76b-d66b-4688-a099-71512ec1f51e'
     expect(actual).toEqual expected
 
-
-###############################################################################
-# z.util.format_bytes
-###############################################################################
 describe 'z.util.format_bytes', ->
   it 'renders 0 bytes', ->
     actual = z.util.format_bytes 0
@@ -231,10 +202,6 @@ describe 'z.util.format_bytes', ->
     actual = z.util.format_bytes 25 * 1024 * 1024 * 1024
     expect(actual).toEqual '25GB'
 
-
-###############################################################################
-# z.util.get_file_extension
-###############################################################################
 describe 'z.util.get_file_extension', ->
   it 'returns common extensions', ->
     expect(z.util.get_file_extension('file.jpg')).toEqual 'jpg'
@@ -255,10 +222,6 @@ describe 'z.util.get_file_extension', ->
     actual = z.util.get_file_extension 'path/to/image.jpg'
     expect(actual).toEqual 'jpg'
 
-
-###############################################################################
-# z.util.trim_file_extension
-###############################################################################
 describe 'z.util.trim_file_extension', ->
   it 'returns the filename without extension', ->
     actual = z.util.trim_file_extension 'image.jpg'
@@ -276,9 +239,6 @@ describe 'z.util.trim_file_extension', ->
     actual = z.util.trim_file_extension 'archive.tar.gz'
     expect(actual).toEqual 'archive'
 
-###############################################################################
-# z.util.ko_array_push_all
-###############################################################################
 describe 'z.util.ko_array_push_all', ->
   it 'appends multiple items', ->
     actual = ko.observableArray [1, 2]
@@ -286,10 +246,6 @@ describe 'z.util.ko_array_push_all', ->
     expected = [1, 2, 3, 4]
     expect(actual()).toEqual expected
 
-
-###############################################################################
-# z.util.ko_array_unshift_all
-###############################################################################
 describe 'z.util.ko_array_unshift_all', ->
   it 'prepends multiple items', ->
     actual = ko.observableArray [3, 4]
@@ -297,10 +253,6 @@ describe 'z.util.ko_array_unshift_all', ->
     expected = [1, 2, 3, 4]
     expect(actual()).toEqual expected
 
-
-###############################################################################
-# z.util.contains
-###############################################################################
 describe 'z.util.contains', ->
   string = 'Club Zeta'
 
@@ -320,10 +272,6 @@ describe 'z.util.contains', ->
     actual = z.util.contains string, 'wurst'
     expect(actual).toBeFalsy()
 
-
-###############################################################################
-# z.util.base64_to_array
-###############################################################################
 describe 'z.util.base64_to_array', ->
   it 'can convert a gif', ->
     actual = z.util.base64_to_array 'data:image/gif;base64,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'
@@ -337,20 +285,12 @@ describe 'z.util.base64_to_array', ->
       buffer_decoded = z.util.base64_to_array buffer_encoded
       expect(buffer_decoded).toEqual array
 
-
-###############################################################################
-# z.util.google_uri_to_e164
-###############################################################################
 describe 'z.util.phone_uri_to_e164', ->
   it 'can convert a Google phone number uri', ->
     actual = z.util.phone_uri_to_e164 'tel:+49-151-50304525'
     expected = '+4915150304525'
     expect(actual).toBe expected
 
-
-###############################################################################
-# z.util.strip_data_uri
-###############################################################################
 describe 'z.util.strip_data_uri', ->
   it 'can strip data uri', ->
     base64 = 'AAAAAAA'
@@ -367,10 +307,6 @@ describe 'z.util.strip_data_uri', ->
     expect(base64_png).toBe base64
     expect(base64_jpg).toBe base64
 
-
-###############################################################################
-# z.util.phone_number_to_e164
-###############################################################################
 describe 'z.util.phone_number_to_e164', ->
   it 'can convert a US number', ->
     actual = z.util.phone_number_to_e164 '555-666-7777', 'US'
@@ -392,20 +328,12 @@ describe 'z.util.phone_number_to_e164', ->
     expected = ''
     expect(actual).toBe expected
 
-
-###############################################################################
-# z.util.get_content_type_from_data_url
-###############################################################################
 describe 'z.util.get_content_type_from_data_url', ->
   it 'can extract the type of a an image', ->
     actual = z.util.get_content_type_from_data_url 'data:image/gif;base64,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'
     expected = 'image/gif'
     expect(actual).toEqual expected
 
-
-###############################################################################
-# z.util.sort_groups_by_last_event
-###############################################################################
 describe 'z.util.sort_groups_by_last_event', ->
   it 'finds out that Group A is more recent than Group B', ->
     group_a = new z.entity.Conversation()
@@ -451,10 +379,6 @@ describe 'z.util.sort_groups_by_last_event', ->
 
     expect(actual).toEqual expected
 
-
-###############################################################################
-# z.util.sort_user_by_first_name
-###############################################################################
 xdescribe 'z.util.sort_user_by_first_name', ->
   it 'can sort a list of users', ->
     user_a = new z.entity.User()
@@ -470,10 +394,6 @@ xdescribe 'z.util.sort_user_by_first_name', ->
 
     expect(actual).toEqual expected
 
-
-###############################################################################
-# z.util.array_get_next
-###############################################################################
 describe 'z.util.array_get_next', ->
   a = 'a'
   b = 'b'
@@ -502,10 +422,6 @@ describe 'z.util.array_get_next', ->
     expected = null
     expect(actual).toEqual expected
 
-
-###############################################################################
-# z.util.array_is_last
-###############################################################################
 describe 'z.util.array_is_last', ->
   a = 'a'
   b = 'b'
@@ -525,10 +441,6 @@ describe 'z.util.array_is_last', ->
     actual = z.util.array_is_last array, d
     expect(actual).toBeFalsy()
 
-
-###############################################################################
-# z.util.array_is_last
-###############################################################################
 describe 'z.util.trunc_text', ->
   it 'returns the full string if it is shorter than the target length', ->
     text = z.util.trunc_text "#{lorem_ipsum.substr 0, 80}", 90
@@ -550,10 +462,6 @@ describe 'z.util.trunc_text', ->
     expect(text.length).toBe 70
     expect(text.charAt 69).toBe '…'
 
-
-###############################################################################
-# z.util.strip_url_wrapper
-###############################################################################
 describe 'z.util.strip_url_wrapper', ->
   it 'return the string without url wrapper (single quotes)', ->
     text = z.util.strip_url_wrapper "url('/path/to/image/image.png')"
@@ -567,10 +475,6 @@ describe 'z.util.strip_url_wrapper', ->
     text = z.util.strip_url_wrapper 'url(/path/to/image/image.png)'
     expect(text).toBe '/path/to/image/image.png'
 
-
-###############################################################################
-# z.util.naked_url
-###############################################################################
 describe 'z.util.naked_url', ->
   it 'returns into naked url', ->
 
@@ -599,18 +503,11 @@ describe 'z.util.naked_url', ->
   it 'returns empty string if url is not set', ->
     expect(z.util.naked_url()).toBe ''
 
-###############################################################################
-# z.util.string_format
-###############################################################################
 describe 'z.util.string_format', ->
   it 'returns string with replaced placeholder', ->
     actual = z.util.string_format 'foo={0}&bar={1}', 1, 2
     expect(actual).toBe 'foo=1&bar=2'
 
-
-###############################################################################
-# z.util.array_chunks
-###############################################################################
 describe 'z.util.array_chunks', ->
   arr = null
 
@@ -641,18 +538,11 @@ describe 'z.util.array_chunks', ->
     expect(actual[3].length).toBe 1
     expect(arr.length).toBe 10
 
-###############################################################################
-# z.util.remove_line_breaks
-###############################################################################
 describe 'z.util.remove_line_breaks', ->
   it 'removes all the line breaks', ->
     actual = z.util.remove_line_breaks 'A\nB\nC\nD'
     expect(actual).toBe 'ABCD'
 
-
-###############################################################################
-# z.util.trim_line_breaks
-###############################################################################
 describe 'z.util.trim_line_breaks', ->
   it 'does not remove line breaks in between', ->
     actual = z.util.trim_line_breaks 'A\nB\nC\nD'
@@ -670,10 +560,6 @@ describe 'z.util.trim_line_breaks', ->
     actual = z.util.trim_line_breaks '\n\n\n\nB\nC\n\n\n\n\n'
     expect(actual).toBe 'B\nC'
 
-
-###############################################################################
-# z.util.append_url_parameter
-###############################################################################
 describe 'z.util.append_url_parameter', ->
   it 'append param with & when url contains param', ->
     url = 'foo.com?bar=true'
@@ -685,19 +571,11 @@ describe 'z.util.append_url_parameter', ->
     actual = z.util.append_url_parameter url, 'fum=true'
     expect(actual).toBe 'foo.com?fum=true'
 
-
-###############################################################################
-# z.util.get_url_parameter
-###############################################################################
 describe 'z.util.get_url_parameter', ->
   it 'get param with no arguments', ->
     actual = z.util.get_url_parameter 'foo'
     expect(actual).toBe null
 
-
-###############################################################################
-# Markdown Rendering
-###############################################################################
 describe 'Markdown for bold text', ->
   it 'renders bold text', ->
     text = '**bold text (not italic)**'
@@ -828,9 +706,8 @@ describe 'Markdown for code snippets', ->
 
 describe 'Markdown with mixed markups', ->
   it 'renders font weights together with links', ->
-    # TODO: Someday we need a link factory (Factory Pattern!)
-    link_1 = '<a href="http://www.link.com" target="_blank" rel="nofollow">www.link.com</a>'
-    link_2 = '<a href="http://www.anotherlink.net" target="_blank" rel="nofollow">www.anotherlink.net</a>'
+    link_1 = '<a href="http://www.link.com" target="_blank" rel="nofollow noopener noreferrer">www.link.com</a>'
+    link_2 = '<a href="http://www.anotherlink.net" target="_blank" rel="nofollow noopener noreferrer">www.anotherlink.net</a>'
     text = "This is *italic* and **bold** and ***bold-italic*** with a www.link.com and www.anotherlink.net."
 
     actual = z.util.render_message text
@@ -869,10 +746,6 @@ describe 'Markdown exceptions', ->
     actual = z.util.render_message text
     expect(actual).toBe text
 
-
-###############################################################################
-# z.util.append_url_parameter
-###############################################################################
 describe 'z.util.print_devices_id', ->
   it 'can print device id', ->
     actual = z.util.print_devices_id '66e66c79e8d1dea4'
@@ -882,10 +755,6 @@ describe 'z.util.print_devices_id', ->
     actual = z.util.print_devices_id '6e66c79e8d1dea4'
     expect(actual).toBe "<span class='device-id-part'>06</span><span class='device-id-part'>e6</span><span class='device-id-part'>6c</span><span class='device-id-part'>79</span><span class='device-id-part'>e8</span><span class='device-id-part'>d1</span><span class='device-id-part'>de</span><span class='device-id-part'>a4</span>"
 
-
-###############################################################################
-# z.util.append_url_parameter
-###############################################################################
 describe 'z.util.zero_padding', ->
   it 'should add zero padding when string length is smaller then max', ->
     actual = z.util.zero_padding '1', 10
@@ -903,10 +772,6 @@ describe 'z.util.zero_padding', ->
     actual = z.util.zero_padding 42, 10
     expect(actual).toBe '0000000042'
 
-
-###############################################################################
-# z.util.append_url_parameter
-###############################################################################
 describe 'z.util.format_seconds', ->
   it 'should format seconds', ->
     expect(z.util.format_seconds(50)).toBe '00:50'
@@ -923,10 +788,6 @@ describe 'z.util.format_seconds', ->
   it 'should format undefined as 00:00', ->
     expect(z.util.format_seconds()).toBe '00:00'
 
-
-###############################################################################
-# z.util.is_same_location
-###############################################################################
 describe 'z.util.is_same_location', ->
   it 'returns false if page was accessed directly', ->
     actual = z.util.is_same_location '', 'https://app.wire.com'
@@ -980,10 +841,6 @@ describe 'z.util.is_same_location', ->
     actual = z.util.is_same_location 'https://app.wire.com/?hl=de', 'https://app.wire.com/?hl=de'
     expect(actual).toBeTruthy()
 
-
-###############################################################################
-# z.util.merge_objects
-###############################################################################
 describe 'Merging objects', ->
   it 'merges two objects into a new one without modifying the sources', ->
     object_a =
@@ -1024,10 +881,6 @@ describe 'Merging objects', ->
     expect(merged_object.ordering.c).toBe 3
     expect(merged_object.ordering.d).toBe 4
 
-
-###############################################################################
-# z.util.bucket_values
-###############################################################################
 describe 'bucket_values', ->
   it 'returns correct value for zero', ->
     expect(z.util.bucket_values 0, [0, 5, 10, 15, 20, 25]).toBe '0'
@@ -1040,10 +893,6 @@ describe 'bucket_values', ->
     expect(z.util.bucket_values 100, [0, 5, 10, 15, 20, 25]).toBe '26-'
     expect(z.util.bucket_values 10023, [0, 100, 200, 500, 1000, 2000]).toBe '2001-'
 
-
-###############################################################################
-# z.util.iterate_array_index
-###############################################################################
 describe 'iterate_array_index', ->
   it 'returns undefined in case of wrong input parameters', ->
     expect(z.util.iterate_array_index 'Test', 0).toBe undefined
@@ -1057,10 +906,6 @@ describe 'iterate_array_index', ->
     expect(z.util.iterate_array_index [1, 2, 3, 4, 5], 3).toBe 4
     expect(z.util.iterate_array_index [1, 2, 3, 4, 5], 4).toBe 0
 
-
-###############################################################################
-# z.util.zero_padding
-###############################################################################
 describe 'z.util.zero_padding', ->
   it 'can add one zero to 6', ->
     actual = z.util.zero_padding 6
@@ -1076,3 +921,19 @@ describe 'z.util.zero_padding', ->
     actual = z.util.zero_padding 666
     expected = '666'
     expect(actual).toEqual expected
+
+describe 'z.util.safe_window_open', ->
+  it 'doesn\'t contain a reference to the opening tab', ->
+    url = 'https://wire.com/'
+
+    new_window = window.open url
+    expect(new_window.opener).not.toBeNull()
+
+    new_window = z.util.safe_window_open url
+    expect(new_window.opener).toBeNull()
+
+  it 'add http if protocol is missing', ->
+    url = 'wire.com/'
+
+    new_window = window.open url
+    expect(new_window.location).not.toBe 'http://wire.com/'
diff --git a/trans.py b/trans.py
index f36eb82b121..2fddacc32e4 100755
--- a/trans.py
+++ b/trans.py
@@ -18,22 +18,31 @@
 #
 
 import os
+import sys
 
-os.system('crowdin-cli-py upload sources')
-os.system('crowdin-cli-py download')
+home_dir = os.path.expanduser('~')
+user_config = os.path.join(home_dir, '.crowdin.yaml')
 
-os.chdir(os.path.dirname(os.path.realpath(__file__)))
-root = 'app/script/localization/'
+os.system('crowdin-cli-py --identity={} upload sources'.format(user_config))
+os.system('crowdin-cli-py --identity={} download'.format(user_config))
 
+os.chdir(os.path.dirname(os.path.realpath(__file__)))
 
 def get_locale(filename):
   locale = filename.replace('strings-', '').replace('.coffee', '')
   return locale if len(locale) == 2 else None
 
+root = 'app/script/localization/'
 
 for filename in os.listdir(root):
   locale = get_locale(filename)
   if locale:
+    if locale != 'de':
+      file_to_delete = os.path.join(root, filename)
+      sys.stdout.write('Removing unsupported locale "{}" ({})\n'.format(locale, file_to_delete))
+      os.remove(file_to_delete)
+      continue
+
     with open(os.path.join(root, filename), 'r') as f:
       source = f.read()