Openfire already supports granting/revoking Admin state via the #admin namespace: https://github.com/igniterealtime/Openfire/blob/299f727c502714a4aea4692e40d29f63 50aadc94/src/java/org/jivesoftware/openfire/muc/spi/IQAdminHandler.java#L288
Thanks for reporting. Re-opened 
SMACK-371, it looks like this are the ownly remains left.