To activate other php-fpm versions, the fpm-services need to be restarted. Under CentOS7 ispconfig has "systemctl restart php-fpm.service" hardcoded (see web-module) due to systemd Result: switching php-fpm versions under CentOS7 is not possible in default ispconfig. Solutions: Option1: create service dependencies of php-fpm in systemd under CentOS7. In that case a tutorial is needed for proper dependencies. Option2: If OS=CentOS7+ Then initd-script-path=systemd name. So that ispconfig can restart the individual services. Needs a rewrite of web-module. Option3: Add another field in php-fpm properties "systemd-name". Needs a rewrite of web-module. Option4: ignore CentOS7-"patch". Since CentOS7+ can still handle initd scripts if properly configured, there is actually no need to handle CentOS seperately. Just use the initd scripts.