[OnWriting]

This completely goes against Apple's guidelines 3.1.2(a):

If you are changing your existing app to a subscription-based business model, you should not take away the primary functionality existing users have already paid for. For example, let customers who have already purchased a “full game unlock” continue to access the full game after you introduce a subscription model for new customers.

I wonder if there will be any repercussions. I doubt it.