Google is continuing to push Android developers to use the latest API features. Last November, all applications submitted to the store were required to target Android 8.0 Oreo or higher — meaning they would have to support runtime permissions and other breaking API changes. As expected, Google is now stepping up the requirements.

Starting in August 2019, presumably around the time Android Q will be released, all new apps will be required to target Android 9 Pie (API Level 28) or higher. In other words, applications can still support whatever minimum Android version they want — even going back to Android 1.0 — but the apps will also have to be built with Android Pie in mind. In November, all app updates will have to target Pie as well. Applications that aren't being updated won't be affected.

Google Play Protect will also start warning users when they try to install outdated apps from outside the Play Store. In August, users will receive warnings when they attempt to install an app not built for Android 8.0 Oreo (API Level 26) or higher. In November, this will be expanded to updating existing apps.

As Google has previously stated, these requirements will advance each year. For example, Google will likely require apps to target Android Q starting in August 2020.

Source: Android Developers

Thanks: Nick