We have no immediate plans to support 3.2 Milestone releases until a few more Milestones come out and the development stabalizes a bit more.
I would add that there is no indication that 4.0 won’t work on 3.2, just no one has tried it yet. So maybe you could try it and let us know? Keep in mind if you run into any problems though our first suggestion is going to be to do a clean reinstall of 3.1 GA.