Is it possible to generate promo codes for in app purchases?

I have a free app with one in app purchase option, and I'd like to offer that IAP for free to some helpful users. In iTunes Connect it appears I can generate promo codes but those codes appear to be for the app itself (which, again, is free so I don't get it.)

Google searching brings up all sorts of claims that Apple doesn't allow you to create promo codes for in app purchases, but those threads are a couple of years old now. Can promo codes be created for IAP or is it just for apps themselves?


It's possible since October 28, 2016, see Apple's guide.

iTunes Connect screenshot