Hello!

Our app uses Apple’s original transaction identifier as the user ID, which is set either when the receipt is validated on the device (which is immediately after a purchase) or possibly via the App Store notification.

We’re running into problems in a subset of our users where part of that subset seems to only have server side app store notification purchase history events, and some users never have a server event attributed to them, just the client side events. It seems likely to me that they just aren’t being merged correctly, although the originalTransactionId should be the same between both (and static, as per Apple docs).

I found a help page here that suggests that setting the user ID on the server side can be problematic, which we think might happen if Apple sends us the notification (and we send an event to Amplitude) before the client receives the receipt and calls setUserId.

The result is that while we still get all the purchase history, that large subset of users is a mystery because we can’t attribute it to them.

Has anyone encountered this before? Is there a way to merge the data, or is it all lost and only fixable going forward?

Thanks,

Richard