From 3c91f99008b11a0390d20ee85734454f8737cee1 Mon Sep 17 00:00:00 2001
From: otsmr <git@tsmr.eu>
Date: Fri, 24 Apr 2026 23:38:07 +0200
Subject: [PATCH] downgrade duplicated error message and fixing new upload of
 message

---
 lib/src/services/api/server_messages.api.dart  | 6 +++++-
 lib/src/services/signal/encryption.signal.dart | 8 +++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/src/services/api/server_messages.api.dart b/lib/src/services/api/server_messages.api.dart
index a94f9b6e..f9e3136a 100644
--- a/lib/src/services/api/server_messages.api.dart
+++ b/lib/src/services/api/server_messages.api.dart
@@ -226,11 +226,15 @@ Future<(EncryptedContent?, PlaintextContent?)> handleEncryptedMessageRaw(
   );
 
   if (encryptedContent == null) {
+    if (decryptionErrorType == null) {
+      // Duplicate message
+      return (null, null);
+    }
     return (
       null,
       PlaintextContent()
         ..decryptionErrorMessage = (PlaintextContent_DecryptionErrorMessage()
-          ..type = decryptionErrorType!),
+          ..type = decryptionErrorType),
     );
   }
 
diff --git a/lib/src/services/signal/encryption.signal.dart b/lib/src/services/signal/encryption.signal.dart
index 96aee2b5..a50b7ca5 100644
--- a/lib/src/services/signal/encryption.signal.dart
+++ b/lib/src/services/signal/encryption.signal.dart
@@ -59,7 +59,13 @@ signalDecryptMessage(
       return (EncryptedContent.fromBuffer(plaintext), null);
     } on InvalidKeyIdException catch (e) {
       Log.warn(e);
-      return (null, PlaintextContent_DecryptionErrorMessage_Type.PREKEY_UNKNOWN);
+      return (
+        null,
+        PlaintextContent_DecryptionErrorMessage_Type.PREKEY_UNKNOWN,
+      );
+    } on DuplicateMessageException catch (e) {
+      Log.info(e.toString());
+      return (null, null);
     } on InvalidMessageException catch (e) {
       if (!resyncedUsers.contains(fromUserId)) {
         if (await handleSessionResync(fromUserId)) {