Openfire (formerly Wildfire) is a real-time collaboration (RTC) server. It uses the only widely adopted open protocol for instant messaging, XMPP (also called Jabber). Openfire is incredibly easy to setup and administer, but offers rock-solid security and performance. License: GNU General Public License v2 Changes:
A security flaw allowed authentication to be bypassed, allowing arbitrary code execution. This was fixed. JDBC and JID optimizations were done.