TOPICLOCK causes ChanServ to revert topic changes by users without the +t flag. Topic changes during netsplits or services outages will always be reverted.
Note: TOPICLOCK requires KEEPTOPIC and will automatically enable it; disabling KEEPTOPIC will disable TOPICLOCK also
tu turn it on
/msg ChanServ SET #foo TOPICLOCK ON
to turn it off
/msg ChanServ SET #foo TOPICLOCK OFF