(Funnily enough, the Cisco in-house messaging and video calling solution we use at my work, through which we also receive landline calls, is still running on XMPP to this day, so I sorta became a XMPP user after all…except I haven’t started this software in 10 months because fuck landline calls and we have better alternatives for chatting.)
XMPP is still chugging along on the backends of stuff like that. I’m not sure but I think WhatsApp has some XMPP in it still.
The most ironic one though is Jitsi, which is what Matrix uses/used (until they started working on Element Calls) to do video calls.