If you create a catmander tag and select (No.) in the settings to allow uninvited players. If they type /squadjoin then it’ll allow them to join. Likewise if you select (Yes, with approval.) that option works, but if you then select (No.) again it will keep asking for their approval.
If you swap to the old tags and then select (No.) then switch back to the new Catmander tag, then no one can join if you have that option set.