Tried with iPad Air and iOS 13.3 - all works fine.
iPad 2 with iOS 9.3.6 - app instantly closes itself after launch.
It seems the issue is in "old" devices. No one really wants to support them now.
That's a pity, I really liked to read with iPad 2 - there is no fighting for it at home, it's too old to run games, etc. So I can take it any time to read, and it always is free.