There was a short discussion last month about development targets for 
Android. I thought folks might find this interesting. It looks like a 
good current target would be 2.2 or 2.3 although I just bumped my Fire 
up to 4.0.4 and I'm really liking it.

--rick

http://www.androidpolice.com/2012/07/02/android-platform-distribution-updated-10-9-on-android-4-0-22-7-still-on-2-2-and-below/