IOS Non-Renewable IAP - Device Limit

Question

We are looking at using a expendable (non-renewable) IAP to subscribe to our application after rejecting to subscribe to automatic renewal. I read a lot of posts related to this, but did not see any discussions on limiting the number of iOS devices that the user can use for expendable or "restore".

The basic concept seems to allow the user to create an account (optional) on your server and allow them to enter account information to restore / share multiple devices.

My main question is: how can we limit the number of devices on which the user is allowed to use the subscription, as well as the number of devices that the user is allowed to “restore”, and still meet Apple’s requirements for restoring purchases?

If we set up the server and allow the user to additionally create an account to store information about the receipt, how can we keep this user from sharing his account with anyone if we do not have the ability to unambiguously monitor the number of unique devices that use the account? (maybe I'm wrong here, but with the outdated UUID and the ability to change the forAdvertising identifier, if the application is uninstalled and reinstalled, there is no way to cache a unique device to determine how many devices used the subscription, fix it?)

I intended to store the authentication token in the user's iCloud, but in my opinion there is no upper limit on how many devices an iCloud account can share.

I am sure that I am not the first to encounter this problem, how do they solve all this?

Thanks - Matt

Answer 1

Consumable items are intended for use in devices. And once consumed, the user must buy it again, even if it was purchased earlier on this device.

Apple does not officially want you to limit the number of subscription devices or supplies — they want your IAP subscriptions and supplies to be available on ALL user devices. See: https://developer.apple.com/library/mac/documentation/NetworkingInternet/Conceptual/StoreKitGuide/APIOverview/OverviewoftheStoreKitAPI.html

Why not use iCloud to transfer non-renewable IAP subscriptions between devices? This limits it to a set of user devices. Why do you care if they have 2 devices or 10? I’m sure that users usually don’t share their Apple ID outside their immediate family.