Store the receipt permanently so you have a paper trail. But for your internal bookkeeping I’d recommend creating a data structure that is platform-independent. A subscription for each package you offer, with an enum specifying each possible status of that subscription. Update the data structure for a user in a way that conforms to what the user purchased. Then you have one thing you can read, regardless of which app store the purchase was made on, and regardless of whatever changes to receipt format the app store owners might introduce in the future.