yum install epel-release
yum install http://rpms.remirepo.net/enterprise/remi-release-7.rpm
yum-config-manager --enable remi-php72
yum update
yum remove php71-php php70-php php55-php php54-php
systemctl restart httpd
yum-config-manager --disable remi-php54 remi-php55 remi-php-54-debuginfo remi-php55-debuginfo