An administrator is upgrading a vCenter Server Appliance and wants to ensure that all the prerequisites are met. What action must be taken before upgrading the vCenter Server Appliance?

The vCenter Server Appliance installer is delivered as a browser-based UI that relies on the Client Integration Plug-in to mount the installer ISO, connect to the target ESXi host, and complete the staged deployment. Without the plug-in installed, the wizard cannot initialize, making it a mandatory prerequisite before any upgrade step can begin.

The VCSA uses an embedded PostgreSQL database and does not require an external database client to be installed as an upgrade prerequisite.

ODBC connectors are relevant only for Windows-based vCenter installations using external SQL databases - the appliance model does not use ODBC.

The Update Manager Plug-in is used to access vSphere Update Manager functionality post-deployment and is not a prerequisite for upgrading the appliance itself.