Repositories configuration:
On Fedora, standards repositories are enough, on Enterprise Linux (RHEL, CentOS) the Extra Packages for Enterprise Linux (EPEL) repository must be configured, and on RHEL the optional channel must be enabled.
Fedora 27
wget http://rpms.remirepo.net/fedora/remi-release-27.rpm dnf install remi-release-27.rpm
Fedora 26
wget http://rpms.remirepo.net/fedora/remi-release-26.rpm dnf install remi-release-26.rpm
RHEL version 7.4
wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm wget http://rpms.remirepo.net/enterprise/remi-release-7.rpm rpm -Uvh remi-release-7.rpm epel-release-latest-7.noarch.rpm subscription-manager repos --enable=rhel-7-server-optional-rpms
RHEL version 6.9
wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm wget http://rpms.remirepo.net/enterprise/remi-release-6.rpm rpm -Uvh remi-release-6.rpm epel-release-latest-6.noarch.rpm rhn-channel --add --channel=rhel-$(uname -i)-server-optional-6
CentOS version 7.4
wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm wget http://rpms.remirepo.net/enterprise/remi-release-7.rpm rpm -Uvh remi-release-7.rpm epel-release-latest-7.noarch.rpm
CentOS version 6.9
wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm wget http://rpms.remirepo.net/enterprise/remi-release-6.rpm rpm -Uvh remi-release-6.rpm epel-release-latest-6.noarch.rpm
remi-php72 repository activation
Needed packages are in the remi-safe (enabled by default) and remi-php72 repositories, the latest is not enabled by default (administrator choice according to the desired PHP version).
RHEL or CentOS
yum install yum-utils yum-config-manager --enable remi-php72
Fedora
dnf install dnf-plugins-core dnf config-manager --set-enabled remi-php72
PHP upgrade
By choice, the packages have the same name than in the distribution, so a simple update is enough:
yum update
That’s all 🙂
$ php -v PHP 7.2.0 (cli) (built: Nov 28 2017 10:27:47) ( NTS ) Copyright (c) 1997-2017 The PHP Group Zend Engine v3.2.0, Copyright (c) 1998-2017 Zend Technologies    with Zend OPcache v7.2.0, Copyright (c) 1999-2017, by Zend Technologies    with Xdebug v2.6.0alpha1, Copyright (c) 2002-2017, by Derick Rethans