Google has ended support for Android 4.0, Ice Cream Sandwich for future Play Service API releases.
What this means is that, Google is instead having developers target API level 16 (for Android 4.1 Jelly Bean) as the minimum level of support.
Though in theory, developers can maintain and roll out updates for a version of their apps specifically for Ice Cream Sandwich users, but it’s highly unlikely that most of them would do it because as of October 26th, only 0.03 percent of Android users were still running Ice Cream Sandwich.
For quite some time now, Google has been trying to push developers to release apps which target the latest version of Android. Last month Google made it mandatory for app developers to ,to target Android 8.0 and higher.
Currently out of 2 billion+ monthly active Android users, majority run on Android 7.0 Nougat followed by Android 6.0 Marshmallow and Android 8.0 Oreo.