I currently experienced the Sony crackle app is not supporting full 21:9 cinematic screen which is one of the best features on the Xperia 1, 10, 10 plus.
It will be great if Sony can work on it to bring the best experience to their customers. That's one of the reasons I purchased the Xperia 10 plus. It is a bit disappointing to watch movies that are currently not supporting the full 21:9 screen.
Hope there is an update for the Sony crackle app to fix the problem.