I know that when I write my apps I can set the minimum OS version so it won't upset folk to download it and it not work.
Maybe that's all you needed to know?
I have two MiTraveler tablets. I can go to android market and search for Angry Birds and get it on the one with android 4.0. It's not even listed when I do a search on the android 2.2 tablet. I don't know if the versions make a difference.