PHP 5.2 brings lots of little useful features and CentOS 5.3 comes with PHP 5.1. So most of my PHP apps failed. The easiest way to solve this is to :
Edit
/etc/yum.repos.d/CentOS-Testing.repo
and put this:[c5-testing] name=CentOS-5 Testing baseurl=http://dev.centos.org/centos/5/testing/$basearch/ enabled=1 gpgcheck=1 gpgkey=http://dev.centos.org/centos/RPM-GPG-KEY-CentOS-testing
Launch:
yum update php
Source : Fresh Blurbs