Missing FPM as an option

Operating system: Centos 6
OS version:Centos 6
I am missing php-fpm from some websites, and these websites are running older php5.3.3 due to using this server to migrate to newer versions of PHP. How do I get that option for FPM under server options? I have the php-fpm packages installed, and refreshed the server config and it shows that it finds php-fpm installed as well.

Does this apply to your situation (restored domain backups, but also a changed PHP version on the same system could cause it I think): PHP-FPM option not available for restored servers

If you have multiple versions of PHP installed on your system and FPM has been configured for some versions of PHP but not for the other versions / all versions of PHP, then Virtualmin behaves the way you have described.

For example, some websites / virtual servers will offer FPM as an option if the currently selected version of PHP has been configured to use FPM while other websites / virtual servers will not offer FPM as an option under Virtualmin -> Server Configuration -> Website Options: PHP script execution mode.

To use FPM on a particular website / virtual server, you must either change the currently selected version of PHP via Virtualmin -> Server Configuration -> PHP Versions to a version of PHP installed on your system that supports FPM or install FPM for the currently selected version of PHP that you are using.