We have two Apps live on the Appstore. One for free, and one full featured version which is offered to buy. The free app has a In-App-Store so the user may update to the full featured version.
Actually I am thinking about stoping development of the full featured App (which is identical
to the free one at code level). We don’t want to blame our customers. It would be nice to give them a redemption code for the free app to unlock all features. All features which will be unlocked this way are bound to the redemption code. All customers who did In-App purchases are “registered” by Apple, so the purchase will be remembered for all devices. Finally all In-App customers would have an advantage over the Pro-Version customers, which is not acceptable for us.
Is it possible to have one (hidden) free In-App purchase, which the user could “buy” if the redemption code is working? Maybe a better question is: What is the best practice for putting two similar Apps together without bugging the customers?
Not possible, I’m afraid. There is no good solution as far as I am aware (I still have a paid and a “lite” version for this reason).
You could raise a bug report with Apple (http://bugreporter.apple.com) but there’s no saying if of when they’ll ever make a change.