I'm going to upgrade system PHP to version 5.4 on server where Parallels Plesk Panel 4.5.9 is installed. Is it possible?
According to System Requirements Parallels Plesk Sitebuilder 4.5.9 works with self-compiled PHP 5.2 (
PHP 5.2.x (shipped in the php5sb package of Plesk Sitebuilder)
Upgrading system PHP to version above 5.2 is not supported.