In app purchase related doubts

My app offers auto renewable subscriptions,

I have couple of questions regarding how to model the subscriptions at server side,

  1. Is originalTransactionId will ever change for a subscription? Will it stay same in case of subscription upgrade/downgrade/crossgrade? If it changes on product change then how do i keep track that the subscription was a continuous subscription and not a new one?

  2. Is the webhook payload contains any identifier of which apple account purchase the subscription?

  3. I am having issues maintaining sync between the app account's current subscription and the local apple account's subscription, is there any doc regarding this? Will be really helpful

In app purchase related doubts
 
 
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