[krschultz]

There is a big gap between the phones on Gingerbread (Android API level 10) and post Ice Cream Sandwich (Android API level 15). Supporting older versions requires a lot of support libraries which themselves have some bugs. I kind of have a feeling that pre-ICS level phones is going to be in someways be like supporting IE6 down the road, so Facebook is just avoiding that.

It's also definitely not a 'handful' of phones. As of right now 55% of users are on the post-ICS versions. (http://developer.android.com/about/dashboards/index.html). The ecosystem has somewhat consolidated post ICS as well. There are now fewer phones each with more users which makes testing easier.