I´m trying to use XMPP´s message event interface. As far as I understand you can mark a message you send with a \'delivery notification requested\' flag and the recipient is
You should get a packet-trace of the XMPP connection, either via wireshark or via the smack debug option, to assure that the delivery notifications are really send by the other end of the connection. If not, this would explain why the listeners aren't called.
Message events in SMACK are done via the now obsolete XEP-22. There is a good chance that the other side does not implement this out-dated mechanism.
That´s all too confusing. Now I use DefaultPacketExtension and send myself the events I need. That´s far more simple, easy to understand and it works.