When a user in forum enables this setting in preference “Only allow specific users to send me personal messages”
New users can’t pm the user, but people who already have conversations or in old PMs still able to send messages?
How to fix this? how to stop all people from sending messages and allow only specific ones for all messages?
Edit: I did it again. This is feature, not support. Sorry about that! 
Edit: oh! It started in bug. It’s not me this time.
Right. That setting keeps you from starting a new topic, but does not delete existing topics (PMs are topics).
Delete the topics or delete the users from the topics.
Moved this to feature request for now and cleaned up title
Thanks, please put this in the next release. 