After you upgrade vCenter Server, and vSphere Update Manager if you are using Update Manager, upgrade or migrate VMware ESX 4.x and ESXi 4.x hosts, or update ESXi 5.0.x hosts, to ESXi 5.x.

These topics are intended for administrators who are upgrading ESX, ESXi, and virtual machines from ESX 4.x/ESXi 4.x, or updating ESXi 5.0.x, to ESXi 5.x.