With a lot of traditional software you buy it once and then pay a lesser price for occasional major version updates. I kind of liked that model, but it's not directly supported by the app store. What is the recommended replacement - subscriptions? I can see a few ways to do it...
1. A subscription (probably yearly). If the subscription expires, then the app could keep running but disable the new features added after the subscription expired.
2. Non-consumable IAP to enable the full features of each major version. So you'd have IAPs like "Full app version 1", "Full app version 2", ...
3. Non-consumable IAP to enable features sets. Similar to #2 but instead of naming them by version I'd have to name groups of features.
I guess I like #1 but it's new to me and I'm afraid it will scare away users because it's asking for a continuous payment.
