Stoat (formerly known as Revolt) is a selfhostable, FOSS replacement for discord [Group chats and voice channels you can join any time].
Cool new name, however not as easy to use in other languages.
Voice chat is stil not officialy implemented.
Self-hosting there. Apparently nothing to do for you if you had already hosted before the name change.
The Android app has unfortunately disappeared (not been updated) on F-droid.
Edit: added short description for clarification
Gotcha that does match my impression.
You’re right though, there’s value in it being a drop-in replacement for discord. Along those lines, I’m very excited for cinny, a matrix discord-like frontend. There’s a PR for voice calls that I check every now and then, the moment that goes in I’ll be trying to convince my friends to hop over.