So I’m not quite clear how you are supposed to update to patch version 7.81. It shows its available but running sudo apt update && sudo apt upgrade seemingly does not update Mattermost (via Omnibus on Ubuntu 22.04)
Let me know if it’s OK for you to wait for the release to hit 7.8.1 or if you need help with manually updating the server. It’s not really complicated, all you have to do is replace the binary, everything else should stay the same for the patch releases, but if you’re not affected by a bug in 7.8.0 which got fixed in 7.8.1 or something like that I suggest you wait for the official release.