If a reader has an auto-renewing subscription in our old 2014 app, and we use the same product ID in our new 2015 app will the reader's subscription carry over? Will they still have access to what they already purchased?
Yes, the product IDs can carry over. For details, see step 4 of this article.
Digital Publishing Solution Help | Stratagies for upgrading apps from DPS to DPS 2015
Let us know if you have any questions.