Reading Time: 2 minutes After the vCenter Server (described in the previous post) and the VUM part (this could a simple upgrade, by keeping the existing DB, or a re-install), you can go through the ESXi part. A re-install from scratch could be simple, but you may loose some information (unless you use Host Profiles). For more information see upgrading to ESXi 5 vs doing a Fresh Install. Note that if you need 3rd part drivers, you may have to build your how ISO version (see: how to add ESXi custom drivers to the installation ISO).