When IAP is purchased the following is correctly displayed. “You’re all set Your purchase was successful.” However, when a previous IAP is restored, purchase will be restored but there is no feedback/notification displayed. Therefore, after an IAP is successfully restored, the following feedback/notification would be very helpful (similar to when the app is purchased): “You’re all set Your purchase has been successfully restored” I understand this is not related to coding by the developer but has to do with the apples in-app purchase process.

Family sharing is not working for IAP although family sharing is enabled on Appstore connect.

If the "restore" button is clicked and there was no previous purchase, currently nothing happens. Ideally there should be feedback/notification saying that “No previous purchase was identified.” Any idea, how this can be set up?

When the full version of the app was purchased before the IAP was implemented, the original purchase is not restored and there is no feedback/notification. Ideally, this should also allow a restoration of the purchase.