Originally Posted by
Apple
11.6 Content subscriptions using IAP must last a minimum of 7 days and be available to the user from all of their iOS devices
If you choose to use user registration to meet this requirement, please keep in mind that it is not appropriate to require user registration. Such user registration must be made optional. It would be appropriate to make it clear to the user that only by registering will they be able to access the content from all of their iOS devices; and to provide them a way to register later, if they wish to access the content on their other iOS devices at a future time.