Anyone who has purchased any IAP content at all has an IAP receipt that you have access to even across installs.
This leaves the problem that v>1 first time buyers will have to IAP something immediately after buying the app, kind of pushes you to have a free trial mode.
Hopefully apple will eventually introduce time-limited free trials and upgrade options. If their history with iOS and Mac versioning is any hint, the current simple system is not a religious thing for them and they will listen if they see enough negative feedback. Which we should provide.
This leaves the problem that v>1 first time buyers will have to IAP something immediately after buying the app, kind of pushes you to have a free trial mode.
Hopefully apple will eventually introduce time-limited free trials and upgrade options. If their history with iOS and Mac versioning is any hint, the current simple system is not a religious thing for them and they will listen if they see enough negative feedback. Which we should provide.