An Android Compatibility Definition Document (CDD) specifies the requirements that must be met in order for devices to be compatible with a specific Android release. This is a public document that is available from Android Compatibility. Compliance with the CDD is mandatory for all devices that want to use the Android name. For example, a Nexus 5 officially running Android 5.0 is required to be complaint with the Android 5.0 CDD.

The CDD is expected to be released to the public along with the source code for each major Android release. However, as of 16 December 2014, more than one month since the Android 5.0 source code was released [1], the Android 5.0 CDD hasn’t been released to the public. As some devices are already officially running Android 5.0, I guess that the CDD has been finalised but for some reason it is being withheld from the public. This is like the 3.0 Honeycomb release situation when Android temporarily became closed source because source code was intentionally not released to the public.

I hope that this situation doesn’t continue for long and that the CDD gets released to the public very soon now.

[1] Android 5.0 Lollipop source code was released on 03 November 2014. It began rolling out to Nexus phones on 12 November 2014.

Update: Android 5.0 CDD was released on 11 January 2015 and is available at http://source.android.com/compatibility/5.0/android-5.0-cdd.pdf.