Why can't we downgrade the PAN-OS on 7500 to below 11.1.3?

When we attempt to downgrade the software of PA-7500 to the lower versions of PAN-OS 11.1 than 11.1.3, the attempt is failed with the following console log messages.

Error: Downgrade from 11.1.3 to 11.1.2 not allowed, only downgrades to 11.1.3 or greater allowed.

Are there any other ways to downgrade the software running in PA-7500 to the lower versions?

• PA-7500
• PAN-OS 11.1.3 or later
• Attempt to downgrade the software to the version < 11.1.3

1. Beginning with PAN-OS 11.1.3, PA-7500 Series firewalls support an NGFW cluster of two firewalls that provide redundancy in the event of a link failure, card failure, or chassis failure.
2. This is documented PAN-OS | NGFW Clustering.
3. So the downgrade is only allowed to version PAN-OS 11.1.3 or greater versions.