It is important to validate the support and compatibility of all vCenter Server dependencies before upgrading the vCenter Server. This is the most important process. Secondly, determining the correct upgrade order will ensure that compatibility and interoperability are maintained throughout the upgrade process.

Once the dependencies and interoperability are validated, the upgrade order for components has been determined, and the supporting components have been upgraded to ensure interoperability, the process of upgrading the vCenter Server itself will be a simple process. The Windows installer for vCenter Server on Windows and the VCSA installer both include upgrade installers to upgrade previous versions of vCenter. The following screenshot shows the VCSA installer with the Upgrade option:

To upgrade a Windows vCenter Server, simply run the installer from the installation media. The installer will detect the previous version of vCenter Server and perform an in-place upgrade. This means the existing application will be updated on the existing server. This is different than the Blue-Green upgrade model used for the VCSA.

When you are upgrading an existing vCenter Server environment, consider the following:

• Upgrading a Windows vCenter Server that was deployed using the Simple Install will upgrade the vCenter Server with an embedded PSC
• Upgrading a VCSA deployed with embedded SSO will upgrade the VCSA with the embedded PSC
• If Microsoft SQL Express was used for the vCenter deployment, the vCenter database will be migrated to the embedded vPostgreSQL database
• A vCenter Server cannot be downgraded after the upgrade. Back up the vCenter Server databases and other supporting components, in the event that you need to revert back to the previous version after the upgrade