Look at my code. I want to change the unfulfilled to fulfilled and update the delivery number.

[Drivebird]

How should I change the code?

My developer suddenly quit so I tried but we originally used the 2021-07 version of api and now we can't make a choice so we chose 2023-04. I've tried a number of ways and I've been given a successful response eventually, but nothing has changed in Shopify.
Can you tell me how to change the code?

The code of our system is php.

[Shayne]

Hi there!

This is a case where you'll likely need to hire another developer to make the required changes. The endpoint that you're using (orders/order_id/fulfullments.json) has been deprecated for a couple of years now in favour of a new system called fulfillment orders. 

Unfortunately this isn't a migration where we'll be able to tell you to switch a couple of params in an endpoint and get the app to work, you'll likely need help from a developer to dig into your existing codebase and make the required updates to migrate. Some core concepts have changed about how fulfillments are managed.

If you're looking for vetted experts, try to visit https://experts.shopify.com/ to hire a freelancer who can help.