http://www.telegraph.co.uk/technology/apple/9327871/WWDC-Apple-highlights-Android-fragmentation.htmlAnd this, coupled with all of phone and hardware variations is why we have "Fragmendroid" phones with only 7% of users having the latest and greatest.
Ah, the tired old "fragmentation" myth comes out again. It has never been satisfactorily explained to me why this is such a big deal with Android, while Windows has the same or even greater "fragmentation" yet continues to thrive.