Update: Plesk 12 supports multiple PHP versions out of the box! This post will cover the install of multiple PHP versions on Plesk 11.5. This is tested on a TransIP CentOS 6.4 x64 VPS with stock repos + EPEL & REMI. This is written for CentOS but with a bit of imagination this can also work on any other linux OS supported by Plesk. Requirements Host running Plesk 11.