FortiGate-VM supports ESXi 5.5 and later versions. Using corresponding hardware versions 10 and later is highly recommended, as Virtual machine hardware versions mentions.
Upgrading hardware versions incrementally with only one delta at a time is recommended. For example, upgrading from 10 to 11, 11 to 12, 12 to 13, then 13 to 14 is recommended, although directly upgrading from 10 to 14 generally has no issues.
- Log in to vSphere Client.
- Right-click the FortiGate-VM in the left Hosts and Clusters window.
- Go to Compatibility > Schedule VM Compatibility Upgrade, then click YES.
- A dropdown list shows all the available VM hardware versions. Select the desired compatibility, then click OK.
- Reboot the FortiGate-VM.