[menny]

I think that he means that it is tricky. He doesn't hide this fact, but it is a know fact, and programmers should be award of it and its possible solutions.

Android dev provides some: http://android-developers.blogspot.com/2010/07/how-to-have-y... And I found some more: http://blog.evendanan.net/2011/04/Backward-compatibility-in-...