To be compatible with a new API release does an Android app need to be rebuilt

Question

To be compatible with a new API release does an Android app need to be rebuilt?

I have searched but cannot find any developer based notes advising this or anything remotely like this.

I would think that it is something a developer does during the release preview (as part of good practice) but I also would have thought there should be no need because a new OS release must retain compatibility with an older app.

Never the less I have seen first hand, and read comments about apps not refusing to work, laggy, etc. specifically in Lollipop.

Answer 1

With each new OS release, the features and related methods are added to the existing set. While addition of the new features(and its related methods in SDKs) continues, few things become obsolete with time. Such methods are then deprecated from SDKs. These deprecated methods may work in some cases but it is always advised to use newer methods.

The published apps are developed with existing SDKs and it is developer's responsibility to make sure that it also works with newer releases. So it is a good practice to test your app with release preview and confirm that it doesn't break. You can not predict which methods will be getting deprecated so it is necessary that new OS release will be compatible to your app.

To answer your question, it is not mandatory to rebuild the app with new API release. One should always first test it for compatibility with new API. If it breaks then it will become necessary to rebuild it to make it compatible.