Since last month, Ice Cream Sandwich (Android 4.0x) was the big winner, gaining 2.7% to come in at 23.7% of the pie, while Jelly Bean (Android 4.1) added just over half a point to come in at 1.8%. Gingerbread (Android 2.3) still makes up the majority of the ecosystem at 55.5%, but that is down just 1.7% from last month. Froyo also dropped just 1.1% to come in at 12.9%.
October is lining up to be a bit more of the same with just some slow movement. But, we should see some interesting shifts come November and December, especially if the rumors of Android 4.2 are correct.
source: Android Developers