Update --
All of our CentOS 6 servers have been updated to 6.7.
Just a quick note. We're in the process of upgrading all of our public DNS servers to the CR release of CentOS 6 - this means that they will for all intents and purposes be running the test version of CentOS 6.7. We're doing this due to an issue in BIND - the DNS server software, which can allow denial of service attacks against BIND. We will upgrade all the CentOS 6 systems to 6.7 when it is released.