The is a legacy firewall that is now officially end-of-life (EOL) and does not support the latest FortiOS releases. For users still operating this hardware, the "best" firmware is generally considered to be the most stable version within the v6.2 release train, as newer mainlines like v6.4 or v7.x are not compatible with the Recommended Firmware Versions
If you are searching for the "," you have likely hit a wall. Searching on Fortinet’s website leads to dead ends, third-party sites are full of malware risks, and your unit might be stuck on an old, vulnerable build (e.g., v5.2 or v5.4). Fortigate 100d Firmware Download BEST
: For most users, FortiOS v6.2.15 is considered the most stable and feature-complete version for this hardware. The is a legacy firewall that is now
After testing hundreds of units, the community consensus for the firmware for the 100D is: : For most users, FortiOS v6