Hi @jirasith
(Firewall A = currently active firewall, firewall B = currently passive firewall)
- Download PAN-OS 8.1.19 to both firewalls
- Install 8.1.19 and reboot firewall B
- Download PAN-OS 9.0.0 to firewall B
- Download PAN-OS 9.0.13, install it and reboot firewall B
- Install PAN-OS 8.1.19 on firewall A and reboot (when you click reboot a failover is done to firewall B)
- Download PAN-OS 9.0.0 to firewall A
- Download PAN-OS 9.0.13, install it and reboot firewall A
- Download PAN-OS 9.1.0 to both firewalls
- Download PAN-OS 9.1.10 to both firewalls
- Install PAN-OS 9.1.10 on firewall A and reboot (when you click reboot a failover is done to firewall B)
- Install PAN-OS 9.1.10 on firewall B and reboot
To make sure that you can downgrade in case of any problems export the configuration at all of the following steps on both firewalls:
- Installation of 8.1.19
- Installation of 9.0.13
