I ran into some errors with my PHP modules on a CentOS server running ISPConfig to host web sites. I decided instead of in depth troubleshooting that it might be easier to go ahead and upgrade PHP since by default the yum package manager will limit you to PHP version 5.1 yet I knew that PHP version 5.2 had been out for a long time. What I needed to do was locate a yum repository that would allow me to upgrade PHP to version 5.2 using yum. The catch was to make sure that every necessary PHP module had an updated package available via the new yum repository. Below I describe upgrading PHP version 5.1 to PHP version 5.2 on CentOS running ISPConfig.