Here's the first one I found that causes server<->server incompatibility: https://xmpp.org/extensions/attic/xep-0369-0.7.1.html
What was always missing was a golden set of standards. Maybe XMPP "2" is XMPP and a set of XEPs and so on.
Otherwise all you have is a bunch of half-working XMPP implementations.
Very famous ones of course include voice/video. The UX on that is atrocious.
What kind of incompatibilities does it cause? It's an unfinished spec for group chats, which, to my knowledge is barely implemented anywhere.
Just for the record I'm using both XMPP and Matrix daily and both have issues :/
Here's the first one I found that causes server<->server incompatibility: https://xmpp.org/extensions/attic/xep-0369-0.7.1.html
What was always missing was a golden set of standards. Maybe XMPP "2" is XMPP and a set of XEPs and so on.
Otherwise all you have is a bunch of half-working XMPP implementations.
Very famous ones of course include voice/video. The UX on that is atrocious.