Roundcube script installation fails "as it requires PHP version 5".

Hello. I want to install RoundCube under virtualmin but I got this error:

This script cannot be installed, as it requires PHP version 5. This script cannot be installed, as this virtual server does not meet its requirements : Could not work out exact PHP version.

However, according to RoundCube site, versions 1.2+ support PHP7 (the version I have on server). The script on server is 1.2.2. Why virtualmin asks for PHP5 then? What should I check as possible source of this error?

My system is: Operating system FreeBSD 10.3 Webmin version 1.810 Virtualmin version 5.05

Thanks George