Comment Wire (Score 1) 5
I'm not sure if Wire has new management but I just recently learned they've gone fully open source, are working on federation, and are using an RFC-specified tree-based efficient group chat encryption algorithm. RCS is eventually meant to adopt the same algorithm.
Folks using Telegram Groups (which are unencrypted, actually) might have a look. Yeah, somebody needs to run a server if you don't want intelligence agencies to provide one for you.
I uninstalled Wire years ago when they wouldn't take privacy seriously (yeah, I filed a bug) but it seems like a second look is warranted.