>Apps may allow a user to access previously purchased content or content subscriptions (specifically: magazines, newspapers, books, audio, music, video, access to professional databases, VoIP, cloud storage, and approved services such as classroom management apps), provided that you agree not to directly or indirectly target iOS users to use a purchasing method other than in-app purchase, and your general communications about other purchasing methods are not designed to discourage use of in-app purchase.

According to Apple/Phil Schiller, any application not explicitly mentioned in this category must offer subscriptions as IAP.

>"We didn't extend these exceptions to all software," said Schiller. "Email is not and has never been an exception included in this rule."

Gmail doesn't actually have to offer Google One subscriptions through the Gmail application. I imagine they are covered by the "cloud storage" exception, which makes me wonder if Hey could also get around it by giving Hey users some cloud storage with their email subscription.