How to upgrade FortiGate firmware on HA pair

FortiGate firmware upgrade is a pretty simple and safe task if done correctly. But understanding how it works "inside" could help you troubleshoot if something goes wrong. Prerequisites: Should have a Fortinet account to download new firmware Tested in FortiGate OS versions: from 7.0 to 7.6 Check release information before installing a new version: https://docs.fortinet.com/product/for... https://docs.fortinet.com/product/for... https://docs.fortinet.com/product/for... https://docs.fortinet.com/product/for... Fortinet upgrade path tool: https://docs.fortinet.com/upgrade-too... 00:00 Intro 00:15 Preparations before you start 02:32 Deployment procedure 05:33 What happens during a firmware upgrade 08:18 Expected service interruption 09:09 What could go wrong and how to fix 12:18 Configurations not synchronized 13:10 Support co