Interesting. Some important context (via the Verge):
The change, while potentially important for developers, isn’t quite as significant as it may seem. In an update to the App Store Guidelines in June, Apple already changed its rules to allow developers to communicate with customers outside of their apps, but at that time, they weren’t allowed to contact users about alternate payment options using information obtained inside the app — they would have had to figure out how to obtain their contact info another way. If this proposed agreement is approved, that restriction would no longer be in place, which should make it easier for developers to reach out to users. Still, it’s not what many developers have been asking for: a way to let users know, inside their app, that they don’t have to pay using Apple’s in-app payment system and incur its up-to-30-percent toll.