My websites in Plesk are all running PHP 7.1.5 (7.1.5-centos7.17051211)
FPM application served by Apache
Obviously I still have Vendor OS 5.4.16 in Plesk as it is required to run some apps.
System info:
Version: Plesk Onyx v17.5.3_build1705170317.16 os_CentOS 7
OS: CentOS Linux 7.3.1611
php...
I was under the impression that Plesk users should avoid using Atomic repository as it has been known to corrupt Plesk. Maybe this applies only if you are running Centos as they do not recommend Atomic repo.