From Nov, All Android App Updates in Play Store Must Target Android 8.0

Note this is target not minimum. People can still release apps that will work on older versions of Android.

However, you must "target" Android 8. Targeting a version of Android in your app is basically Android's way of making backwards compatibility work, and it's been great. The Android OS will present certain features to your app based on what version you tell it you are targeting.

eg. Android 6.0 introduces optional permissions. Android before that made users agree to all permissions at install time. To make sure that all the old apps suddenly didn't break, what version your app targets controls what system of permissions your app uses.

However, this was a problem. Bad actors could avoid optional permissions simply by targeting a Android version lower than 6! I guess that's why Google is pulling this move - so that in the future no-one can opt out of the restrictions.

See the O.P. for far more on what this affects, but this means:

  *  optional permissions
  *  background restrictions
  *  a worse Android ID so tracking is more private

(Also note, this applies to new updates released only. Older releases will continue to work. So not all apps in the Play Store will switch instantly)