Handling 'lifetime' subscriptions alongside auto-renewing in-app purchases

Question

I would like to offer three subscription options in my app:

1. Monthly recurring
2. Yearly recurring
3. Lifetime

I can setup the monthly and yearly subscriptions as auto-renewable products, and put them in the same group so that upgrades and downgrades are handled nicely. However, the lifetime subscription has to be a regular non-consumable product since the maximum duration for a renewing product is one year.

What can I do to handle users moving from a monthly or yearly subscription to the lifetime subscription? I can't offer any partial refund/credit for remaining time, and most importantly I can't cancel their existing subscription on their behalf. Am I limited to some informational messaging ("Please make sure you cancel your existing subscription") with a link to the Manage Subscriptions settings? Or is there more I can do?

Answer 1

As far as I know you have no possibility to cancel his subscription for him. So before a user can buy the lifetime IAP you have to check if he has an active subscription and if so you need to prompt him to cancel it. Otherwise he would end up with lifetime and a subscription.