1.添加yum repo php5.2.x

vi /etc/yum.repos.d/CentOS-Testing.repo
[c5-testing]
name=CentOS-5 Testing
baseurl=http://dev.centos.org/centos/$releasever/testing/$basearch/
enabled=1
gpgcheck=1
gpgkey=http://dev.centos.org/centos/RPM-GPG-KEY-CentOS-testing
priority=1

2.安装

yum upgrade php