@Override
    public Iterator<String> getFeatures() {
        return Collections.singleton("jabber:iq:version").iterator();
    }
Implements the TYPE_IQ jabber:iq:version protocol (version info). Allows
XMPP entities to query each other's application versions.  The server
will respond with its current version info.

@author Iain Shigeoka
xmppserver/src/main/java/org/jivesoftware/openfire/handler/IQVersionHandler.java