1) Log into the web-based manager as the admin administrative user.
2) Go to System > Firmware > Click on the "Browse" button to locate the firmware image file.
3) Locate the file on your local computer and select the firmware image file.
4) Click on "Backup config and upgrade" button to back up the configuration and start firmware upgrade.
5) The FortiGate unit uploads the firmware image file, upgrades to the new firmware version, restarts, and displays the FortiGate login. This process takes a few minutes.
See HA status below-
