Google is looking for ways to every manufacturer equips its terminals with the latest version of Android to stop fragmentation and ensure that users do not have to wait months (and in some cases the wait is forever) to have the latest version. The way to force install the more recent versions would be to give a few months to raise version, at the risk of which it is not possible to gain access later to the Google Apps.
The point is that manufacturers believe that leave users stranded in earlier versions of Android force the replacement of equipment and know that is not so There is no reason to change each year a mobile that works perfectly only for being the last.
Google applications that could not be entered in a model that has Android earlier in the term which would give Google would be Gmail, Drive, Hangouts, Search, YouTube and especially Google Play Stored. You know that a phone that can not access the store is practically useless for most users. This decision seems very hard, but Google thinks it’s the best way to force manufacturers to improve operating systems in each model.
Thus, manufacturers who want to launch their handsets with Android 4.2 (API version 17) have a deadline to do so on April 24. If you want to integrate the 4.3, have until July 31. From then on will only have nine months after the launch of a new version of Android are taking to continue terminals with an earlier version that was just released.
To see if updated properly medium to low range that still offer versions of Android with 3 years old mobile and the current scheme decided updates manufacturers have no ability to upload version.