Can I migrate purchase between applications in mac

Question

I have several similar applications (A1-A3) with hugely the same codebase. They all do similar things (diagrams), each with a specialisation for a specific use case. I am now considering to create one app (B) that sells the specialisations as an Mac App Store In App Purchase. So basically, I reduce number of applications, but will provide same diagrams, just change how to sell them from dedicated app to in-app.

How can I best ensure that buyers of the "old" applications A1-A3 can use the specialisations they bought in the new software B? I don’t want to charge them twice. So, they should be able to “restore” the specialisation that they bought as a A2 in B. Is that possible? If so, how?

Answer 1

Within app B do following steps in the background or on click of the restore IAP-button:

• Look for the "old" app A1-A3 using NSBundle bundleWithIdentifier
• get the receipt of this bundle using appStoreReceiptURL
• validate the receipt
• unlock functionality

Bare in mind that the terms and conditions of Apple say something along the line of "only appstore IAP should be used to unlock features; don't roll your own license mechanism"