public void setChangeNickname(boolean canChange) {
        this.canChangeNickname = canChange;
    }
Sets if room occupants are allowed to change their nicknames in the room. By default,
occupants are allowed to change their nicknames. A not_acceptable error will be returned if
an occupant tries to change his nickname and this feature is not enabled.

Notice that this feature is not supported by the MUC spec so answering a not_acceptable
error may break some clients.

@param canChange if room occupants are allowed to change their nicknames in the room.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/MUCRoom.java