默认的版本太低了，手动安装有一些麻烦，想采用Yum安装的可以使用下面的方案：
1.检查当前安装的PHP包
yum list installed | grep PHP
如果有安装的PHP包，先删除他们
yum remove PHP.x86_64 PHP-cli.x86_64 PHP-common.x86_64 PHP-gd.x86_64 PHP-ldap.x86_64 PHP-mbstring.x86_64 PHP-mcrypt.x86_64 PHP-MysqL.x86_64 PHP-pdo.x86_64
2.Centos 5.X
rpm -Uvh http://mirror.webtatic.com/yum/el5/latest.rpm
CentOs 6.x
rpm -Uvh http://mirror.webtatic.com/yum/el6/latest.rpm
CentOs 7.X
rpm -Uvh https://mirror.webtatic.com/yum/el7/epel-release.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
如果想删除上面安装的包，重新安装
rpm -qa | grep webstatic
rpm -e 上面搜索到的包即可

3.运行yum install
yum install PHP55w.x86_64 PHP55w-cli.x86_64 PHP55w-common.x86_64 PHP55w-gd.x86_64 PHP55w-ldap.x86_64 PHP55w-mbstring.x86_64 PHP55w-mcrypt.x86_64 PHP55w-MysqL.x86_64 PHP55w-pdo.x86_64

yum install PHP56w.x86_64 PHP56w-cli.x86_64 PHP56w-common.x86_64 PHP56w-gd.x86_64 PHP56w-ldap.x86_64 PHP56w-mbstring.x86_64 PHP56w-mcrypt.x86_64 PHP56w-MysqL.x86_64 PHP56w-pdo.x86_64

注：如果想升级到5.6把上面的55w换成56w就可以了。

yum install PHP70w.x86_64 PHP70w-cli.x86_64 PHP70w-common.x86_64 PHP70w-gd.x86_64 PHP70w-ldap.x86_64 PHP70w-mbstring.x86_64 PHP70w-mcrypt.x86_64 PHP70w-MysqL.x86_64 PHP70w-pdo.x86_64
4.安装PHP FPM
yum install PHP55w-fpm
yum install PHP56w-fpm
yum install PHP70w-fpm
注：如果想升级到5.6把上面的55w换成56w就可以了。