When a device is active (non-EOL), the "best" firmware is simply the latest general release. For the 100D, the logic changes. Here is what "BEST" means in the EOL context:
Distributing or downloading FortiOS firmware outside official channels violates Fortinet’s End User License Agreement (EULA). How to Access Official Downloads To get legitimate firmware files:
Re: Fortigate 100D Best & Latest stable firmware - Fortinet Community Fortigate 100d Firmware Download BEST
Check the Fortinet Technical Documentation for the specific release notes of the firmware you are downloading to confirm compatibility with the FortiGate 100D. 3. Best Practices for Upgrading (Don't Skip This!)
Because the FortiGate 100D is an aging platform operating on a legacy firmware branch, it faces growing operational limitations. FortiOS 6.2 no longer receives new feature updates, and signatures for modern threat matrices can strain older hardware resources. When a device is active (non-EOL), the "best"
branch (such as 6.0.12 or 6.0.13) if they experience performance issues on 6.2, though 6.2.15 is the official final release. Restriction : The 100D
The FortiGate 100D does not support FortiOS 6.4, 7.0, or higher. Its hardware architecture limits it to the FortiOS 6.2 release train. How to Access Official Downloads To get legitimate
The is an older hardware model that has reached its maximum supported firmware version. The best and final stable firmware for this device is FortiOS 6.2.15 . 🛠️ Firmware Compatibility & Selection
If you cannot legally obtain the 5.4.13 firmware because your support contract expired a decade ago, you have two options: