Perform a configuration backup before every single step in the upgrade chain.
The latest supported firmware for the is FortiOS 6.0.18 . fortigate 200d latest firmware
The . While it remains a stable platform for legacy internal segmentation or a lab environment, it is dangerous for edge security . Fortinet has moved on to the 40F, 60F, 80F, and 100F series, which offer 10x the performance and full security updates. Perform a configuration backup before every single step