I am running VirtualMin/Webmin on CentOS 6.5.
I am unable to determine how to properely upgrade to PHP 5.4 or any version above PHP 5.3.3 without causing issues to VirtualMin/Webmin.
Any help with upgrading the PHP version would be much appreciated.
There unfortunately isn’t a recommended way to upgrade PHP. We always recommend using the PHP version that comes with your distro.
PHP versions from other repositories are known to cause config problems, and enabling other repositories can cause unusual problems in general.
If at all possible, the recommended way to upgrade would be to wait until CentOS 7 comes out, and to upgrade to that.