"We talk about, say, RHEL 5 or CentOS 7, but each of these versions has sub-versions and they do fall out of support over time.... Now, there's a difference between applying patches for, say, version 6.2 and updating from 6.2 to 6.3: in-version patches will generally not affect applications, but minor version upgrades have a higher risk. "
I don't know about RHEL and derivatives but for Debian regular patching brings it up to the current version number. e.g:
cat /etc/debian_version
7.11
and yet it started out at 7.0.
Biting the hand that feeds IT
