According to this answer, push tokens are regularly rotated to help with privacy, and that my web service API implementation will see this as a new registration.
Does this mean that the web service API registration endpoint must detect the same device library identifier with a different pushToken as a different device? Or, does the device library identifier also change with the pushToken?
Both the device library identifier and the push token are regularly randomised. When a push token is rotated, you will receive a registration request with a new device library identifier and push token. You will not receive an I register request for the old identifier and token.
When making a push request for a token that has been rotated, you will receive a response from APNS letting you know that the token is no longer valid.
Therefore, when a device has rotated it’s token and you haven’t sent a push request, your database should show it registered with 2 identifiers.