In the upcoming Red Hat Enterprise Linux 8 distribution, the way software is organized has changed: critical packages are now contained in the BaseOs repository, while the AppStream one contains multiple versions of some of the most common used applications and programming languages which are organized in modules, and updated independently of the distribution release cycle. This strategy has been adopted in order to avoid the problem of being stuck with a certain, too outdated or too recent release of a certain software.
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-install-php-on-redhat-8