To install, first you must add the Webtatic EL yum repository information corresponding to your CentOS/RHEL version to yum:
CentOS/RHEL 7.x:
rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
CentOS/RHEL 6.x:
rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm rpm -Uvh https://mirror.webtatic.com/yum/el6/latest.rpm
Remove old php version
yum remove php*
Now you can install PHP 5.6’s mod_php SAPI (along with an opcode cache) by doing:
yum install php56w php56w-cli php56w-common php56w-devel php56w-gd php56w-imap php56w-intl php56w-mbstring php56w-mcrypt php56w-mysql php56w-pdo php56w-xml php56w-xmlrpc