@openess@skrivel.se Xmpp has a long history. As matrix it is federated and you can choose Server and client and mix as you want. For self hosting there is @prosodyim@fosstodon.org - might take a good Sunday afternoon to setup. (AFAIK) the same guys work on @snikket_im@fosstodon.org which you can run in 10minutes if you have used docker compose. Resource wise Prosody runs fine on the oldest raspberry pi in your drawer. Or the cheapest 3€/month VPS. Can't compare encryption, OMEMO works fine for me though.