I’m going to talk as if this is going to be added.
That’d sure be nice. But sadly that’d cost a lot for InterAction Studios, even if joining was paid.
And in case it’s made to be a part of the main server, well that’d also weaken the performance of the server.
Plus, in order to do that, iA may need to change the code of older versions, so they can connect to the server properly.
Therefore it’s futile to spend all that effort so older unstable versions can join the game.
There was a more serious topic for that earlier: Test server, which iA responded for. Making a server useful for, well, catching cheats and debugging easily is a bad idea, therefore having a server made for older versions would be pretty futile.
Make a whole server just so Early access versions or older releases can still play.