for this model. Using a device past its EOSL date is generally discouraged for production environments, as it may remain vulnerable to Common Vulnerabilities and Exposures (CVEs) discovered after its final update. Upgrade and Replacement
While the 5.6 train is significantly outdated compared to current releases, it was the last stable branch compatible with the 80C's hardware. Users still operating this device cannot upgrade further because newer versions of FortiOS require more memory and processing power than the 80C provides. Lifecycle and Support Status FortiGate 80C followed a standard Fortinet Product Life Cycle until it was phased out: End of Sale (EOS): January 14, 2018. End of Support (EOSL): January 14, 2023. Router-Switch.com fortigate 80c latest firmware version
However, "latest" does not mean "secure." for this model
The most critical piece of information for administrators is the version number. Users still operating this device cannot upgrade further
The 80C skipped the v5.4, v5.6, and v6.0 major release trains entirely. While newer models like the 80D, 80E, and 80F received updates pushing them into v6.2, v6.4, and even v7.0+, the 80C was officially sunsetted at the v5.2 branch.