I have a question with isEligibleForIntroOffer(for: groupId)
that in which case that isEligibleForIntroOfferForGroupId changes from false to true. I found that a few user of our app isEligibleForIntroOffer changes. they used to buy a renewing-subscription with 3-day free trial. but 3 days later. i got from logs their isEligibleForIntroOffer becomes true. We rely on this field to determine whether to display products with free trials. there is only one product with free trial introductory offer.
I have a question with `isEligibleForIntroOffer(for: groupId)`
An Apple Account typically would not move from ineligible to eligible but this could happen if it was a paid offer that was refunded.
Additionally it depends how you determine a user - eligibility is based on the Apple Account but a device could change what Apple Account is signed-in. While not a common scenario on most devices, some users may do so with shared devices.