messageCollection addedMessages issue after 4.19 version

messageCollection addedMessages issue after 4.19 version

After updating SendbirdChatSDK iOS to 4.19.5, messageCollectionDelegate’s addedMessages makes error.
The situation I found is below.
This is the group channel case, which 2 people participate in.
When user B send message, user A gets message from addedMessage of messageCollectionDelegate.
When all of them was on the chat room (foreground ), It works fine. The message which sent is well transferred.
But when user A gets message from push notification on the background, or other view controller-out of the chat room in the application-, addedmessages works twice.
It gives the correct addeMessages first time, and right after it gives the 20 previous messages again, even though they are already showed above.

I downgraded SendbirdChatSDK iOS 4.18.0 with the same code, and it works fine without error above.

[SDK Version]
SendbirdChatSDK iOS 4.19.5

[Reproduction Steps]
No special code, just using messageCollectionDelegate’s addedMessages.


  • When getting message out of the chat room.
  • After the view is shown again.

[Current impact]
// How is this currently impacting your implementation?