Do we need to opt in for the new Fulfillment Order Workflow?

[typ]

My team received a notification to migrate to the new Fulfillment Order Workflow by Mar. 31st, 2023, and we're a little confused about what will break at that time.

Do we actually need to opt in to the new fulfillment orders workflow, or can we just modify our code to use the new 2023-01 endpoints?

Here is the guide we were referencing:

https://shopify.dev/docs/apps/fulfillment/migrate

Here is the notification we received: