Version 1.3.4 for Windows not autoupdate messages. You have to restart the application to see new messages.
@prokopiy Could you check out current version 1.4.3 and try to reproduce your issue, please? Thanks in advance.
or even better try the upcoming release https://support.delta.chat/t/test-upcomming-desktop-1-10-x-release/1080
Closing as we don't get any more info about this