Install PHP 5.6 on CentOS 7

To install PHP 5.6 on CentOS 7, enable EPEL repo and remi repo

yum install epel-release -y
rpm -ivh https://rpms.remirepo.net/enterprise/remi-release-7.rpm

Install yum-utils and enable remi-php56 repo

yum install yum-utils
yum-config-manager --enable remi-php56

Install PHP 5.6 with

yum install -y php php-bcmath php-cli php-common php-devel php-gd \
    php-imap php-intl php-json php-ldap php-lz4 php-mbstring php-mysqlnd \
    php-soap php-intl php-opcache php-xml php-pdo