After completing the upgrade to vCenter Server, upgrade legacy VMware ESX/ESXi hosts to ESX 4.1/ESXi 4.1.

These topics are intended for administrators who are upgrading ESX, ESXi, and virtual machines from ESX 4.0/ESXi 4.0 to ESX 4.1/ESXi 4.1.

To upgrade directly from ESX 3.5/ESXi 3.5 to ESX 4.1/ESXi 4.1, use VMware vCenter Update Manager. For information on upgrading from ESX 3.5/ESXi 3.5 to ESX 4.1/ESXi 4.1, see the vSphere Update Manager Administration Guide.