Thanks for getting in touch! So, testing the REST updated_tracking endpoint against 2021-10 with your input data, this works fine for me today. Would you mind sending me the x-request_id of this call if you have it, and any error messages you are receiving, and I can try take a look at what’s going on. Thanks!
Through the shopify team, my problem has been solved. In addition to the permission of write_merchant_managed_fulfillment_orders , the permission of write_third_party_fulfillment_orders needs to be added.
Thanks for everyone’s help. This only kind of worked. If you use company foo and url https://foo.bar, in the customer’s order details the Carrier is set to Other, not very useful. If you use company “DPD”, i.e. one that’s in Shopify’s drop down the company is now correct but there is no URL displayed, which in the case of DPD Germany is even less useful.