Unless they’re purchases for goods or services that are consumed outside the app, in which case you are prohibited from using IAP. Unless those goods or services consumed outside the app are magazines, newspapers, books, audio, music, or video, in which case, you are required to use IAP. But if your app only “reads” previously purchased magazines, newspapers, books, audio, music, or video, and doesn’t mention the possibility of purchases anywhere in the app, you don’t need to use IAP.