We are looking for an experienced developer the help with a problem on our Openfire XMPP Server. It is currently not storing offline messages on our MySQL database.
I already worked on the Openfire XMPP server previously and made the real time notification sytem using the same components as you described. I am having a core expertise in PHP and already programmed the PHP system with the XMPP server having a MySQL database alongside for storage. So I could efficiently solve your problem easily.