Upgrading from ESXi 5.5 to ESXi 6.x via SSH using esxcli – VLabWare
Upgrading from ESXi 5.5 to ESXi 6.x via SSH…
If you want to upgraded your ESXi 5.5 server to ESXi 6 you can do using the install ISO file. However, it is also possible to perform the upgrade from 5.5 to 6.0 via SSH and esxcli.