I’m changing from an Android to an iPhone (or vice versa), do I need to pay for the Deluxe app again?

Purchases on Android and iOS are not transferable to each other. This is due to the fact that payments for your Android device are taken by Google. Whereas the payments for your iOS device are taken by Apple. However, if you are transferring from an Android to another Android or iPhone to another iPhone, you will not be charged again for downloading the app again.