Overview: When using PHP packages from the IUS repo, Virtualmin detects that FPM is present but won't allow switching to use php-fpm in the website options.
Background: Typically I prefer using the IUS repo packages for PHP because they've been stable for several years and don't require the version switching that SCL packages do. The IUS repo packages are drop-in replacements for the OS-provided PHP packages; they have the same binary names and paths on the filesystem. Eg, php-cgi, php-fpm, etc.
Using latest Virtualmin version 6.0.1. Installed via minimal mode.
I found a workaround in one of the other issues for specifying the php mode via command line and that worked in my case. However, control panel still wouldn't display the option for FPM.
Testing with php71u packages including php71u-fpm.