Checking the documentation for notification types https://developer.apple.com/documentation/appstoreservernotifications/notification_type I've detected that the behaviour of CANCEL notification has changed. Now, there isn't a CANCEL notification when making an upgrade. The documentation page doesn't mention any change in the behaviour, so it is very difficult to detect this kind of changes. It seems that Apple is trying to drive developers crazy, putting all possible difficulties to our task, and hiding relevant information. Even the documentation pages don't include a modification date, so that we can at least know when a new version has been created.
