Android Phones And Tablets Are Mostly Running 2.x

The API level in the table above identifies the version of the framework API that is issued with the Android release on the device. The framework API is what any app developer would use to get access to the underlying features and capabilities of the Android system. Among other things, it consists of a set of packages and classes, as well as XML elements for declaring and accessing resources and permissions that apps are allowed to request.

Updates to the API are designed to be compatible with all earlier versions of the API.

An example may help: Android has provided a SlidingDrawer widget since Cupcake and API Level 3 (click here to see a simple example in action). Every app developer that wants to provide a draggable handle to display or hide content can use SlidingDrawer, and every subsequent API release will support SlidingDrawer. An app developer that wants to use SIP would need to use the android.net.sip API, which was not introduced until the first release of Gingerbread and API Level 9. The app would want to include an indicator that it's compatible with API Level 9; all later versions of the API would support the app, but earlier versions of Android would know that the app requires some functionality from the API that is not supported in the earlier version.

[Motorola's new Droid 4 phone comes with Android 2.3, but will be upgraded to 4.0. Click here to read BYTE's review.]

While the report is designed to show app developers the percentage of devices that they can be compatible with based on which version of the API that they decide to develop with, the data give a nice at-a-glance view of the penetration of different Android versions.