How Does Linux Kernel Versioning Work?
At any given time, there are several “stable” versions of Linux, and one “development” version. Unlike most proprietary software, older stable versions continue to be supported for as long as there is interest, which is why multiple versions exist. Linux version numbers follow a longstanding tradition. 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. This happens very rarely — in Linux’s history it has happened exactly once. 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. The current stable series is 2.4.x, and the current development series is 2.5.x. However, many people continue to run 2.2.x and ev
