"For a while, CentOS releases lagged noticeably behind RHEL
releases, most notably with the CentOS 6.0 release. The CentOS 6.0
release lagged behind the RHEL 6.0 release by eight months. The 5.x
series has no such delay.
CentOS 5.8 was officially released last week, just a few short
weeks after Red Hat pushed RHEL 5.8 upstream.