Are you still running Android 4.1 or below? Then you will be a victim of what is about to happen. Google has recently join Apple in clearing apps from play store that is not supporting the latest Android OS model.
This way all newly submitted apps should work with the latest Android versions, while the already available ones that fail to update could be retired for good.
"This app was build for an older version of Android and may not work properly. Try checking for updates, or contact the developer."
The current minimum API version set in Android P is 17, which is 4.2 Jelly Bean. We are yet to see if this will remain as a warning in the final version of Android P, or it will block apps from running.
Google's intention will be brought to light once Android P is complete.
Via