What's the duration of a In-App Purchase Promo Code for Auto-Renewable Subscription's? I just can't seem to find any answer to this question on the internet, so it might be good to just ask it here for future reference of people Googling the same question.

In my App, I have a Auto-Renewable Subscription of one month. So it renews every month. I want to hand out a few promo codes to previous beta-testers of my app to thank them for testing out the app.

I know a promo code expires after 28 days of creation. But that does not say anything about the duration of the Auto-Renewable Subscription when that promo code is used.

So, in other words; does the user's subscription expire after one month when using a promo code? Or does that user have a subscription for life when using a promo code?
Got an answer from Apple. They confirm what I thought:


  Promo codes for auto-renewable subscriptions are valid only
  for the duration of the subscription. Subscriptions purchased with a
  promo code do not automatically renew.


So, in my case; one month and then it expires.