Hi guys,
Just to clarify you can transfer any maps purchased on any MUDMAP apps to new apps free of charge so you won't need to pay for them again. This is because your purchase history is attached to your MUDMAP account, so as long as you log in to your MUDMAP account via the new app you will be able to download all the maps you have previously purchased for free.
I hope this helps. If you have any further questions please ask me any time.
Warm Wishes,
Maria from MUDMAP