There isn't much to add to the topic. Similar issues appeared when CentOS 4 or CentOS 5 could not compile packages anymore. New installations of CentOS 6 do not work for a long time already. Existing installations are still running. If we continue providing CustomBuild for EOL systems - it'll just start breaking the things, instead of leaving everything "in-place" and working. For example, latest version of CustomBuild has no support for init.d systems anymore, it's systemd-only. It has no startup scripts for the services, expects components like MariaDB or PHP to always be started in foreground mode, has no component-downgrades or code to custom-compile libraries that are available on newer systems. This error thrown is added there to protect the systems from unexpected behaviour-outages, not to cause them