If we intend to upgrade our VMware ESX hosts 4.0 or VMware ESXi 4.0 to the new version of vSphere 4.1 manually, This is, without using VMware Update Manager we can do it in a simple way. We will only have to download a couple of files, copy them to the host and apply them to update the computer, Previously we will have shut down all the virtual machines that the host runs or we have moved them to other computers and put the computer in maintenance mode.