Before you upgrade vCenter for Windows to vCSA, the PSC must be migrated to the corresponding vSphere version, which in our case is vSphere 6.7.

If you are migrating vCenter for Windows with an embedded PSC, you can skip this step. You can follow these steps to upgrade your PSC:

1. Perform a backup of the Windows Server that hosts the PSC.
2. Mount the installation image of vCenter Server for Windows to the external PSC and start the installation wizard of vCenter Server.
3. The installation will realize that it has been launched on a system that contains a previous version of the vSphere component and the upgrade wizard will be launched.
4. Accept the license agreement and provide an SSO user account.
5. You can change the default ports that PSC will be bound to as well as the installation directories.
6. At the summary windows, you must check that the Windows server was backed up. If not, the installation will not be permitted.
7. Only after the upgrade is completed can you continue with the next steps.