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