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
oh yea their website seems to be down. surely a good sign… in the meantime, you can look at the website/spec through their codeberg repos.
i’m not a huge fan of matrix because it seems very bad to selfhost. from my understanding, if anyone using your homeserver joins a big channel, your homeserver will have to store the entire history of that channel and keep it up to date. on top of that, it very much seems like the spec isn’t being developed by the community, but more that element implements some feature and then forces that into the spec. also polyproto claims to be much more resilient, allowing you to migrate to a new homeserver, even if your old one is already dead.
also a lot of matrix’s funding comes from crypto, ai and venture capital, so i think it’s just a matter of time before the whole project becomes completely subsumed by capital interests