The 613+ betas are unstable builds that I’m working on in order for them to replace the current ‘stable’ 2.1 beta. I think I should have made that clearer from the start, that’s my bad.
So the stable beta is here and will always be here no matter what.
The builds that I post somewhere else (613-617 for example) are, for the time being, research builds so that I can get feedback in order for them to become the official beta. Once that’s happens, there will only be one ‘beta’. Those builds do expire and that’s normal as I don’t want research builds to be kept around for too long, especially if the auto-update is current not working on those.
I’m sorry for the confusion, it’s my bad for getting caught up in getting builds out (finally! I was so excited) and not making this clear.