Basic Concept: For active/passive HA upgrades, the safest method is to upgrade the passive firewall first, fail over to it, then upgrade the remaining peer. This preserves forwarding during most of the process.

Why C is Correct: The selected sequence keeps one firewall forwarding traffic at all times and avoids simultaneous reboots.

Why A is Wrong: From Panorama, create a scheduled software update job targeting both firewalls in the HA pair to run at the same time, then rely on the HA election process to manage the failover automatically. is an HA-related setting or behavior, but it is not the specific HA link, LACP pre-negotiation option, or upgrade sequence required here.

Why B is Wrong: Upgrade the passive firewall first while it is still in the passive state. Once it reboots and is operational, suspend the active firewall to fail over to the newly upgraded device. Then, upgrade the remaining firewall. is an HA-related setting or behavior, but it is not the specific HA link, LACP pre-negotiation option, or upgrade sequence required here.

Why D is Wrong: Disable HA synchronization on the active firewall, upgrade the passive firewall, and then re-enable synchronization. Once synchronized, repeat the process on the other firewall. is an HA-related setting or behavior, but it is not the specific HA link, LACP pre-negotiation option, or upgrade sequence required here.