I know that JEP-0045 is still in draft, but does Jive Messenger support JEP-0045 or any other form of Multi-User Conferencing?
My question was answered by the changes document http://www.jivesoftware.org/builds/documentation/changes.html. MUC support was added to 1.1.
We have about 90% of MUC implemented, I believe. The last bits are being actively worked on. If you follow the standards-jig mailing list on jabber.org, you’'ll see Gato asking many questions about the JEP.