Notifications are only send to users that are subscribed to the topic.
Patch is missing to remove already notified forum-users from the reply notification
Subscribing to a forum means you get notifications for new topics, not posts (this is the way it has always been). If you mean something else, could you please explain what you mean?
In 3.0 when you subscribe to a forum, you receive emails for everything that happens in this forum.
// forum notification is sent to those not already receiving topic notifications
So we should restore this behaviour or add an additional way to do this.
Yes, forum subscriptions are also for new posts.
Oh, I tested it and yes, that's correct. Not sure why I thought it was for only new topics.