My app stop working on Android Pie but my project (very old!) is
compileSdkVersion 21
minSdkVersion 14
targetSdkVersion 21
Do you think I need to rewrite the code that uses WiFiManager to respect the latest Android security restrictions?
You won't be able to publish to Google Play unless you target API 26+, so if you want to publish to Google Play or provide a experience that is consistent with other modern apps, you would need to rewrite your WifiManager
code to comply with the latest Android security restrictions.