diff --git a/mautrix/util/message_send_checkpoint.py b/mautrix/util/message_send_checkpoint.py
index 61eb691d..5dd023b5 100644
--- a/mautrix/util/message_send_checkpoint.py
+++ b/mautrix/util/message_send_checkpoint.py
@@ -29,6 +29,7 @@ class MessageSendCheckpointStatus(SerializableEnum):
     PERM_FAILURE = "PERM_FAILURE"
     UNSUPPORTED = "UNSUPPORTED"
     TIMEOUT = "TIMEOUT"
+    DELIVERY_FAILED = "DELIVERY_FAILED"
 
 
 class MessageSendCheckpointReportedBy(SerializableEnum):