PAN-OS Upgrade / Downgrade procedure

[CarlNeal]

I need to rebuild an HA peer for an existing NGFW in our Azure Production environment with minimal downtime. The existing NGFW was deployed as BYOL (Azure Source image plan = byol). The rebuilt HA Peer has been deployed as PayGo (Azure Source image plan = bundle1). The mismatched PAN-OS version is blocking HA peering and config sync.

I need to UPGRADE the original NGFW to version 11.1.0 and DOWNGRADE the new HA Peer to version 11.1.0 to successfully enable HA Peering and config sync before rebuilding/redepolying NGFW #1 as PayGo.

https://docs.paloaltonetworks.com/vm-series/11-1/vm-series-deployment/set-up-the-vm-series-firewall-...

NGFW #1 (Original)
Model: PA-VM
VM Mode: Microsoft Azure
Software Version: 11.0.2
Azure Source image plan: byol
Azure OS: Linux (centos 8.3.2011)

NGFW #2 (HA Peer)
Model: PA-VM
VM Mode: Microsoft Azure
Software Version: 11.2.3-h3
Azure Source image plan: bundle1
Azure OS: Linux (redhat PanOS)