iOS Receipt validation failing for long-term users

Question

With our latest release, we converted our app from paid to in-app subscription purchase. We promised our current users that we would grandfather them into the subscription because they already paid for the app. In our code, we look for a valid receipt with an original application version prior to our first subscription version. It all worked great in our tests.

When we released the new app, we started getting feedback from our long-term users that they were being asked to subscribe (they shouldn't even see the subscribe button). As we researched the issue, we noticed that all of these users purchased our app prior to the app being transferred to a new developer in September of 2014.

Recreating this issue is difficult - how do we simulate an app install in 2014? I may be able to login as one of the affected users, which would involve using their Apple credentials. I'm not very comfortable asking users to share their credentials.

Since I haven't been able to recreate it and our code is pretty simple, my best guess as to what is happening is that we aren't receiving a valid receipt for users that purchased prior to the app transfer in 2014.

So, I have a few questions:

1. Has anyone else experienced this?
2. If so, how have you resolved it?
3. How would you troubleshoot it?

FYI - I've filed an issue with Apple (3045378).

Answer 1

In speaking with Apple Developer Technical Support, we discovered a way to pull the NSLog messages off of the devices using the recently released Unified Logging feature. A couple of our users submit their logs, which clearly showed that they were getting valid receipts, but the originally purchased versions of those receipts are 4 and 2.8.

Given that our current version is 1.7.1, these are strange and non-typical numbers. However, the Original Application Version reported from the receipt is actually the CFBundleVersion (or Build), which can be a completely different string than the App Version reported in the App Store.

I assume that the developer prior to the app transfer was using a different build numbering system than the standard ... scheme.

I refined the version check within my code and re-submitted the app. It was released today, and, so far, all are being grandfathered correctly.