We’ve resubmitted the HEY Calendar app to Apple
David Heinemeier Hansson
JANUARY 8, 2024
VOIP, Cloud Storage, Email Services , Web Hosting) do not need to use in-app purchase, provided there is no purchasing inside the app, or calls to action for purchase outside of the app. They even cite Email Services(!!) as an example in 3.1.3(f):
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