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Fortinet no longer releases new feature updates for this model.
Or via GUI: System > Firmware > Upload (Ensure "Upgrade" is selected, not "Install" if preserving config). Fortigate 100d Firmware Download BEST
Look for the tag on the latest patch (e.g., FortiOS 6.2.15 or higher, depending on the final security patches released for the D-series). Fortinet no longer releases new feature updates for
"CPU spikes to 100% after upgrade." Fix: This is often the ipsengine going haywire. In CLI, run: diagnose test application ipsmonitor 99 If it crashes, disable "Redline" protocol decoders in your IPS sensor. "CPU spikes to 100% after upgrade
If you are planning this upgrade, I can help you verify the process. Please let me know:
Because the 100D is EOL, Fortinet support agents give you a download link over chat unless you renew a contract (which is impossible officially for the 100D). However, there is a legitimate workaround:
© 2026 WM Lighthouse