admin/environment/php
From MoodleDocs
Moodle has different PHP requirements for different versions.
Moodle 2.0 will require PHP 5.2.4 or later.
Moodle 1.6 to 1.9 requires PHP 4.3.0 or later
Moodle 1.0 to 1.5 requires PHP 4.1.0 or later
Note: You are currently viewing documentation for Moodle 3.4. Up-to-date documentation for the latest stable version of Moodle is likely available here: admin/environment/php.
Moodle has different PHP requirements for different versions.
Moodle 2.0 will require PHP 5.2.4 or later.
Moodle 1.6 to 1.9 requires PHP 4.3.0 or later
Moodle 1.0 to 1.5 requires PHP 4.1.0 or later