When v9 comes out people running v8 will crash when they connect to a v9 server i think. So it would idiotic to have the the mac update and the windows update to be released on different dates because mac users will not be able to play Blockland for a wile. So most likely they will be coming out on the same date. (Unless of course Badspot has other plans)
As said by tommy RTB 2 is just going to be like a large add-on for Blockland so that should be compatible.
