What you are describing is an app crash. It most likely is happening because there is a change in iOS 12.5.7 that the app is not compatible with. Unfortunately we are no longer able to update that version. I have made two major updates that vastly improve the app, but the oldest one requires at least iOS 14. Your iPad cannot be updated to that version. When it comes to updating hardware, Apple does not try to support older hardware. It’s a tough problem, because supporting old hardware leads to a lot of extra code and weird (meaning hard to fix) bugs. This was a major problem for Windows, as they tried to support software from very old versions. I’m sorry to say there is nothing we can do to fix this for you.