Help with HTTP v1 firebase push

I need help with sending remote push using firebase. Currently I am using the Legacy Key to send Push notifications and it is working well. Firebase has an alert: “If you are an existing user of the legacy HTTP or XMPP APIs (deprecated on 6/20/2023), you must migrate to the latest Firebase Cloud Messaging API (HTTP v1) by 6/20/2024.” Are you familiar with this code? there is extremely little documentation and it seems complicated to get it set up correctly on Xcode