To avoid catastrophic failures, you must understand Fortinet’s version numbering scheme. A typical version looks like this:
Upgrading your FortiGate firmware requires careful planning and execution. Follow these best practices: fortigate firmware
Common issues during firmware upgrades include: To avoid catastrophic failures
You can have the latest definitions on an old firmware, but you cannot patch OS-level CVEs with definitions. fortigate firmware
Warning: Avoid upgrading HA clusters where the firmware jump skips more than 3 minor versions.