Seems like there are extensions for threaded discussions. For example, the following XEP (XMPP Extension) talks about best practices for message threads: http

Seems like there are extensions for threaded discussions. For example, the following XEP (XMPP Extension) talks about best practices for message threads: https://xmpp.org/extensions/xep-0201.html https://xmpp.org/extensions/xep-0201.html And XEP-0085 about chat state notifications has a section about threads. https://xmpp.org/extensions/xep-0085.html#bizrules-threads https://xmpp.org/extensions/xep-0085.html#bizrules-threads So probably your best bet is to look at the list of supported features of all XMPP clients and see which ones support XEP-0085, and then between any clients that support that see if they support threading.