The legacy app ended up on targetSdkVersion = 25 (Android 7.1). There have been a few releases since then, especially Android 8 which (as we know) broke some things. We should increase the target to latest if possible, which would be 28 (Android 9.0) in this case. Of course, we also need to increase compileSdkVersion in that case (and there's no reason to not just keep them the same as each other).
The legacy app ended up on targetSdkVersion = 25 (Android 7.1). There have been a few releases since then, especially Android 8 which (as we know) broke some things. We should increase the target to latest if possible, which would be 28 (Android 9.0) in this case. Of course, we also need to increase compileSdkVersion in that case (and there's no reason to not just keep them the same as each other).