Once an app is published to the Play Store, with this new minimum requirement, the minority of users still on legacy platforms will no longer see the app or its updates as being available for their device.
Play Services helps to bypass Android’s fragmentation by enabling Google to deliver new APIs through updates in the Play Store rather than requiring a firmware upgrade each time (which has to be customised for each device and put through carrier testing before it can be deployed.)
Developers are free to continue supporting Gingerbread and Honeycomb themselves with separate app builds – one which makes use of the latest APIs with a minimum API level of 14, and one which only uses APIs included in Play Services until now.
In your build.gradle, the separate versions can be defined with two different dependencies:
versionCode 901 // Min API level 9, v01
versionCode 1401 // Min API level 14, v01
With such a small percentage of Android devices active which does not support a minimum API level of 14, Google’s recommended course of action is to focus on building the newer version. If you have an app with a vast amount of legacy users, you may have little choice.
Along with the change to Play Services, the new minimum API level will also be incorporated into Firebase (part of the platform used for storage of user-generated content like photos and videos.)