What about the customers who have already purchased a paid application when upgrading it on app store to free application with In App purchase? [duplicate]

Answer 1

How about releasing a new paid version which writes some data to the application's data store recording the fact that is the paid edition. Then release a new version of the same app that is free but obviously does not record that. However, the free version looks for the data written by the paid version and unlocks the premium features if that record is found.

The only downside is that you'll be depending all paid users upgrading to the new paid version before you release the free one.

Answer 2

If the switch from paid to free is quite far away from the paid app launch date, it should be more acceptable. What I suggest is to enhance your free version with a new feature\content to satisfy those who had already downloaded and paid for it.

Answer 3

Is there a way to check the version they are upgrading from?

If so, you could make the fully unlocked app version 2.5, and the locked free app version 2.2 and, assuming your current customers are on version 1.9, you simply check for this. If they are on version 1.9, they get "upgraded" to version 2.5.