In general, the upgrade from vCloud Networking and Security to NSX for vSphere is achieved by upgrading vShield Manager with a special VMware-vShield-Manager-Upgrade-bundle-to-NSX upgrade bundle. Currently this upgrade bundle is available for all NSX for vSphere releases, except 6.2.1. VMware recommends upgrading to the highest supported VMware NSX version based on the various solutions and tools incorporated in the service provider environment (vCloud Director, vSphere, and so on).