The SDK's XML deserializer reflects on declared properties of its Data
classes and throws a RuntimeException when QuickBooks returns a field
the installed SDK version doesn't define yet (e.g. the new invoice
AllowOnlinePayPalPayment field), breaking every invoice create/update.
The JSON path builds instances from the class's own known properties
and silently ignores unrecognised response fields instead, so it
tolerates QuickBooks adding fields ahead of the SDK.