1.查看当前 PHP 版本

php -v

查看当前 PHP 相关的安装包，删除之

yum list installed | grep php

yum remove php

yum remove php-*

2.更换 RPM 源

#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

3.安装新版本 PHP

php 7.0/7.1/7.2 分别表示为 70w/71w/72w目前（2018-5-4）CentOs 6.x 的 RPM 源中最高只有 7.1CentOs 7.x 的 RPM 源中有 7.2

yum install -y php71w php71w-cli php71w-common php71w-devel php71w-embedded php71w-fpm php71w-gd php71w-mbstring php71w-mysqlnd php71w-opcache php71w-pdo php71w-xml php71w-ldap php71w-mcrypt

4.再次检查版本

php -v