Whenever the app stops working on a given mobile OS I’m sure the answer will be “run it conventionally.” The same thing will happen to Lionel’s new Base3. All of these Bluetooth/Wi-Fi iThingies will be useless bricks in 20 years, as will the WIU, WTIU, and Base3. It gives me no pleasure to state this fact, but such is technology.
Since these are closed systems, the best we can hope for is that an open source project will get started to reverse engineer all this garbage. Or commodity DCC electronics that work well with larger O sized motors.