holly hell ! How can this be an official solution ? Ok, Android devices upgrade cycle could use improvements, but as far as back compatibility goes, it gets it right. You can publish different versions of your app, so even if you drop an old OS version with 1% of marketshare, you can still let users download the last version of the app for their OS. From an user point of view, it is transparent, you click install and get the last compatible version, period.