Comment 1 for bug 1545777

Thanks so much Christoph. I'm marking this as duplicate, but copying your bug report body content to the other one.

If you don't mind loosing your secret chats, you can do this workaround (note this will remove your secret chat history!):
on the phone (terminal app) or via adb shell from your computer:
rm -rf ~/.config/com.ubuntu.telegram

If you do care about secret chat contents, don't do what I said above, please wait for an update..