Apple has made the server-to-server notifications feature of App Store Connect more useful for developers, with it now providing alerts for when a customer's subscription fails to renew, as well as when it is resolved.
Server-to-server notifications is a service provided by Apple to developers that provides real-time updates for a user's subscription status. In short, the App Store sends a notification to an app's secure server advising of any changes in the subscription status, such as cancellations, renewals, and new subscriptions.
Announced via the Apple Developer Portal, the list of things the notifications will advise has increased, with new notifications sent when a "subscription renewal fails due to a billing issue," along with "when a billing issue is resolved by the App Store."
Apple provides the notifications to developers for a variety of reasons, but chiefly so that the business logic of the app's server can perform a developer's designated actions for that particular situation, While before this could've covered things like advising users of renewal notices before the App Store takes another subscription payment, the new additions let the users be informed from within the app of the payment issues.
Notifications for App Store activity are also a goldmine of data for developers to determine issues within apps. For example, a large number of failures to perform an in-app purchase could indicate an issue with that particular function, drawing developers to more closely examine that area for problems.
As part of the server notification changes, Apple is also including a "unified receipt containing information about the latest 100 in-app purchase translations" along with the two notifications.
Developers who've already enabled server-to-server notifications in App Store Connect will automatically receive the new notifications and unified receipt without needing to change the account settings.