The link to the chapter "Planning an upgrade" redirects to https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/upgrading_from_rhel_8_to_rhel_9/planning-an-upgrade-to-rhel-9_upgrading-from-rhel-8-to-rhel-9 , which results in 404 Not Found. Reported by: zuansorg https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/upgrading_from_rhel_8_to_rhel_9/index#annotations:f7945856-c186-4fdf-9e31-2a0430e0a5fc