OK, upgrading php can be tricky because all web application depends on it. While upgrading the php you need to ensure that you use remi repository along with EPEL.
# rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
# rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
Once Remi repository is installed, use your favorite editor and enabled it.
# vim /etc/yum.repos.d/remi.repo
>>> Edit enabled=0 line to enabled=1:
Now run yum to update the php:
# yum update php
Run this to check the php version
# php -V
Labels: CentOS, php