Just to reinforce this: RHEL/CentOS version numbers cannot be directly compared with the upstream projects version numbers. That is the version that was picked

Just to reinforce this: RHEL/CentOS version numbers cannot be directly compared with the upstream projects version numbers. That is the version that was picked as a base, and then bug fixes are ported back to that version. In this case it is a single patch to deal with TeX support in CentOS 6, but for many other packages it can be dozens of patches to try to get a truly stable version.