zlacker

>>mikece+(OP)
I'd prefer a federated solution, but XMPP doesn't yet have decent support for group chat that doesn't depend on being connected. https://xmpp.org/extensions/attic/xep-0369-0.1.html is still experimental.

Bravo to Signal for being easy enough for my family to use!

>>rodlet+gb
Matrix fixes that issue (and also the issue of the server your group chat is hosted on disappearing). It has plenty of other issues, of course.