I've always understood it to be the case that apps could permit users to log in or use a code to access paid content, as long as the app did not direct the user to an external web site to make a purchase. For example, apps like Netflix or Kindle.
My app isn't even doing anything close to this. I have an app in which digital content is unlocked via in-app purchase. Occasionally I give away promo codes that allow a user to unlock one free piece of content. These codes can only be used once, and are distributed in very limited numbers on cards, in person, at events like trade shows.
My app has been in the store for about four years using this method. This week I attempted to publish a small bug-fix update, and was flagged by Apple and told that my use of Promo Codes in this manner violates the rules.
What happened here? Did Apple misunderstand what my app is doing? Did the rules change recently and I was unaware of the change? Has this always been against the rules, but either Apple didn't enforce it before or they never reviewed my app thorougly enough to find it?
Thanks,
Frank