I don't fully get this. If I try to restore for example a subscription, that the user purchased 6 months ago for one year:
If this subscription is auto renewed after one year, and we restore it again 6 months later: - What is the original purchase date? - What is the purchase date?
My understanding is so far: Purchase date: Is always the time of the restore Original purchase date: Most probably the beginning of the subscription period. But is it the beginning of the first subscription if it is auto renewal? Or is it the beginning of every renewal period?
The receipt field documentation from Apple explains it very well:
Original Purchase Date:
In an auto-renewable subscription receipt, this indicates the beginning of the subscription period
Purchase Date
In an auto-renewable subscription receipt, the purchase date is the date when the subscription was either purchased or renewed
For example: someone bought a yearly auto-renewing subscription on 2019/2/2. When you check it on 2020/2/1 the orignalPurchDate and the purchaseDate are 2019/2/2, whereas on the 2020/2/2 the orignalPurchDate is still 2019/2/2 but for purchaseDate it is 2020/2/2.