If you are in the mid of app development then I assume you had already shared this with your tech team. If they were unable to answer that then you are surely in trouble. Fire them right now! because you don't even know what they will end up building.You might end up getting a rejection from Apple store if the app is not "wired" properly.

On the other note Apple doesn't have any problem with subscription based apps, they have problem with the nature of the app. With recent updates they have provided support with there SDK but have gone very strict with the privacy policy in respect to the end user. Otherwise the billing is through the same old app store billing system (70% dev/ 30% store).

Hope it helps.