Linux Kernel Numbering
How do Linux Versions Work?
At any given time, there are several “stable” versions of Linux, and one “development” version.
Linux kernel numbering convention.
Each version has three numbers, i.e., X.Y.Z.
The “X” is only incremented when a really significant change happens, one that makes software written for one version no longer operate correctly on the other.
The “Y” tells you which development “series” you are in. A stable kernel will always have an “even” number in this position, while a development kernel will always have an “odd” number.
The “Z” specifies which exact version of the kernel you have, and it is incremented on every release.
For a example.
The current RHEL 6.4 uses kernel number 2.6.32-358.
That simply means that we are using 2.6 kernel which is a commercial release and is safe to be deployed on production servers, as it is having a “even” number at second place.
Always remember, that development series (odd number in place Y) is the code that the Linux developers are actively working on, which is always available for public viewing, testing, and even use, although production use is not recommended!