I haven’t been able to find how to block the specific OS version, but it doesn’t matter, as the whole page is blocked for compliance.
We created this config to block the download page entirely. This script is from the command line but can be done in the GUI. As mentioned, you can remove GP client from the firewall as well.
set profiles custom-url-category block-gp-sw-page type “URL List”
set profiles custom-url-category block-gp-sw-page list [ *.example.com/global-protect/getsoftwarepage.esp *.example.com/global-protect/getmsi.esp ]
set rulebase security rules Block-GP-SW-Page to Internet
set rulebase security rules Block-GP-SW-Page from Internet
set rulebase security rules Block-GP-SW-Page source any
set rulebase security rules Block-GP-SW-Page destination any
set rulebase security rules Block-GP-SW-Page source-user any
set rulebase security rules Block-GP-SW-Page category block-gp-sw-page
set rulebase security rules Block-GP-SW-Page application any
set rulebase security rules Block-GP-SW-Page service application-default
set rulebase security rules Block-GP-SW-Page hip-profiles any
set rulebase security rules Block-GP-SW-Page action deny
set rulebase security rules Block-GP-SW-Page rule-type intrazone
set rulebase security rules Block-GP-SW-Page description “Block access to GlobalProtect software download page”
set rulebase security rules Block-GP-SW-Page disabled no
move rulebase security rules Block-GP-SW-Page top