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Hello. I am looking for some advice. Our app offers in-app purchases using Stripe. Users can pay a one-off fee or set up a subscription via the app. There is no other way to pay. Our app was approved but we had a separate issue so we needed to upload a new version. This time the app has been rejected because "your app offers a subscription with a mechanism other than the in-app purchase API." But we only offer in-app purchases. There is no other way to pay other than via the app.We are getting no-where with asking for clarification. The reviewer simply repeats the same sentence. Have other app developers come across this issue? Do we have to use Apple Pay now? Is it obligatory?