Ok ... Beta's are the releases for the foolhardy explorers to use. They are the prototype versions complete with bugs and will go on being produced until the bugs are ironed out and a version appears that is not going to cause the normal user [much] problem
Major releases are the finished product for the normal user to use. (Ithink)
I can't quite suss out what defines the service release.
So 4.9.29 may not be the Major release I thought it was ... maybe it is a service release.
I practiced what I preach and did a search, but came up with some pretty interesting posts from 3 years ago instead so I still haven't got the answer.