After you finish the prerequisites for upgrading, your next step is to update the upgrade coordinator to initiate the upgrade process.
After the upgrade, based on your input, the upgrade coordinator updates the hosts, NSX Edge cluster, NSX Controller cluster, and Management plane.
You can use REST APIs to upgrade your NSX-T Data Center appliance. Identify the NSX-T Data Center version you are upgrading to. Refer to the API guide with your product version in code.vmware.com to find the latest upgrade-related APIs.