I recently set up a server with CentOS 8. I installed PHP 7.3 and 7.4 on the server. I uploaded an older 7.3.5 Dolphin site that I intended to upgrade to 7.4.2 for the owner. Of course the site won't load without php 5.6. No problem of course, I will simply install php 5.6.40 and will be good to go. Well, no. It seems that installing php 5.6.40 can't be done; or can't be done without forcing it. For one, there are changes in the OS libraries that may not allow 5.6.40 to work as it should. Remi indicated that they provided a 5.6.40 if you went to their site and used their wizard to generate a repo. Evidently that has changed because after using the wizard it informed me that nothing less than php 7.2 would be generated to run on CentOS 8. I don't know if I should try to force php 5.6.40 on the server or not.
I do have a server running CentOS 7 and I will probably just use that to upgrade the site and then move it over to the CentOS 8 server. I just wanted to let people know that if you have any sites that need php 5.6 that can't be upgraded, use CentOS 7. You might can force php 5.6 on CentOS 8 but doing a internet search didn't turn up any results for doing so.