Steps for upgrading to PHP7 on CentOS 6 system. Taken from install-php-7-in-centos-6
To install latest PHP 7, you need to add EPEL and Remi repository to your CentOS 6 system
yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
yum install http://rpms.remirepo.net/enterprise/remi-release-6.rpm
Now install yum-utils, a group of useful tools that enhance yum’s default package management features
yum install yum-utils
In this step, you need to enable Remi repository using yum-config-manager utility, as the default repository for installing PHP.
yum-config-manager --enable remi-php70
If you want to install PHP 7.1 or PHP 7.2 on CentOS 6, just enable it as shown.
yum-config-manager --enable remi-php71
yum-config-manager --enable remi-php72
Then finally install PHP 7 on CentOS 6 with all necessary PHP modules using the following command.
yum install php php-mcrypt php-cli php-gd php-curl php-mysql php-ldap php-zip php-fileinfo
Double check the installed version of PHP on your system as follows.
php -V