Is there a way to receive notifications of new version release

  1. Go to the release announcements for Plex Media Server
  2. Scroll to the very end of the thread
  3. Click on Bookmark (not a browser bookmark!)

With the default preferences in your forum settings, you should get e-mail notifications when there’s a new post in this thread (= new release).
There’s no way to have separate notifications for public vs. beta releases.