i have problem after upgrade from jabberd 2.2.17 to 2.3.4 (jabberd2.org)
the problem is known as "packet sent before session start, closing stream" 
after consultation with maintainer i have question about RFC 6120 Compatibility
he said that one of the differences in new RFC is stricter specification of session establishment protocol. Unfortunately this breaks clients using pre-XMPP Jabber session protocol.
Section 7.3.1 of http://xmpp.org/rfcs/rfc6120.html Resource binding is mandatory now. In old Jabber protocol when announcing the presence was binding the resource from presence message implicitly.
what's the status of xmpp library in jitsi?