diff --git a/Simplicity.xcodeproj/project.pbxproj b/Simplicity.xcodeproj/project.pbxproj
index 14421cd..46fccfe 100644
--- a/Simplicity.xcodeproj/project.pbxproj
+++ b/Simplicity.xcodeproj/project.pbxproj
@@ -151,12 +151,12 @@
 		DF74EC271CE2A8BB008F16BF /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 0800;
+				LastUpgradeCheck = 0920;
 				ORGANIZATIONNAME = Stormpath;
 				TargetAttributes = {
 					DF74EC2F1CE2A8BB008F16BF = {
 						CreatedOnToolsVersion = 7.3.1;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0920;
 					};
 				};
 			};
@@ -218,14 +218,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -254,7 +260,7 @@
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = iphoneos;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
@@ -270,14 +276,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -299,7 +311,7 @@
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VALIDATE_PRODUCT = YES;
 				VERSIONING_SYSTEM = "apple-generic";
@@ -324,7 +336,8 @@
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -344,7 +357,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.stormpath.Simplicity;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
diff --git a/Simplicity.xcodeproj/xcshareddata/xcschemes/Simplicity.xcscheme b/Simplicity.xcodeproj/xcshareddata/xcschemes/Simplicity.xcscheme
index 6d0e049..6a74cb1 100644
--- a/Simplicity.xcodeproj/xcshareddata/xcschemes/Simplicity.xcscheme
+++ b/Simplicity.xcodeproj/xcshareddata/xcschemes/Simplicity.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0920"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -36,6 +37,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/Simplicity/LoginProviders/Facebook.swift b/Simplicity/LoginProviders/Facebook.swift
index 1bea523..296a17a 100644
--- a/Simplicity/LoginProviders/Facebook.swift
+++ b/Simplicity/LoginProviders/Facebook.swift
@@ -53,11 +53,11 @@ public class Facebook: OAuth2 {
             let range = urlScheme.range(of: "\\d+", options: .regularExpression) else {
                 preconditionFailure("You must configure your Facebook URL Scheme to use Facebook login.")
         }
-        let clientId = urlScheme.substring(with: range)
+        let clientId = urlScheme[range.lowerBound..<range.upperBound]
         let authorizationEndpoint = URL(string: "https://www.facebook.com/dialog/oauth")!
         let redirectEndpoint = URL(string: urlScheme + "://authorize")!
         
-        super.init(clientId: clientId, authorizationEndpoint: authorizationEndpoint, redirectEndpoint: redirectEndpoint, grantType: .Implicit)
+        super.init(clientId: String(clientId), authorizationEndpoint: authorizationEndpoint, redirectEndpoint: redirectEndpoint, grantType: .Implicit)
     }
 }
 
diff --git a/Simplicity/LoginProviders/VKontakte.swift b/Simplicity/LoginProviders/VKontakte.swift
index 997c65b..4795107 100644
--- a/Simplicity/LoginProviders/VKontakte.swift
+++ b/Simplicity/LoginProviders/VKontakte.swift
@@ -33,10 +33,10 @@ public class VKontakte: OAuth2 {
             let range = urlScheme.range(of: "\\d+", options: .regularExpression) else {
                 preconditionFailure("You must configure your VK URL Scheme to use VK login.")
         }
-        let clientId = urlScheme.substring(with: range)
+        let clientId = urlScheme[range.lowerBound..<range.upperBound]
         let authorizationEndpoint = URL(string: "https://oauth.vk.com/authorize")!
         let redirectEndpoint = URL(string: urlScheme + "://authorize")!
 
-        super.init(clientId: clientId, authorizationEndpoint: authorizationEndpoint, redirectEndpoint: redirectEndpoint, grantType: .Implicit)
+        super.init(clientId: String(clientId), authorizationEndpoint: authorizationEndpoint, redirectEndpoint: redirectEndpoint, grantType: .Implicit)
     }
 }