As a developer of a long-lived popular app I've been pretty agressive at cutting off older OS versions from updates (min sdk 21 right now, considering 23). But

As a developer of a long-lived popular app I've been pretty agressive at cutting off older OS versions from updates (min sdk 21 right now, considering 23). But the Play Store lets you keep serving up an old version of your app for those older devices. So before I cut off an old OS version I make sure to have a solid bug free release that I can serve them for a few years until eventually my backend API server is forced to break backward compatibility at which point I pull it from the app store and serve up an I'm sorry message for anyone trying to run that old version, about 3 years old at this point.