Downgrading to previous firmware versions
FortiManager does not provide a full downgrade path. You can downgrade to a previous firmware release using the GUI or CLI, but this causes configuration loss. A system reset is required after the firmware downgrade. To reset the system, use the following CLI commands via a console port connection:
execute reset {all-settings | all-except-ip}
execute format {disk | disk-ext4 | disk-ext3}