I plan to use non-renewing subscription on SaaS app since apple doesn't allow auto-renewable for SaaS.
Apple also requires us to provide a server side mechanism to track the subscription with multiple devices.
But, based on my research, apple also seems to reject app if registration is mandatory, so such user registration must be made optional.
My app can be used without registration at start, so registering is optional at this point. But, if users want to buy non-renewing subscription, registration is mandatory to track the subscription.
Does apple reject this approach?
Related links:
app rejected.how to track user non-renewing subscription
*UPDATE
I checked the session video of WWDC2012, and it seems it is ok to ask user to register with your server BEFORE purchase for non-renewing subs. I will post an answer once they really approved this method.
*UPDATE
I got an reply from apple through Resolution Center.
The bottom line is we should allow user to buy subscriptions without registration anyway.
This is the answer from apple review team.
It would be appropriate to make registration optional. You may provide an alert stating that the user will not be able to track a subscription on multiple devices without registering. However, you should provide the option to register and track a subscription after the subscription is purchased as well.