Debian

Debian GNU/Linux is an operating system with a focus on stability. It's based on a sophisticated package management system that lets you choose from three releases of varying stability. The software packages included in the stable release have been tested thoroughly and are ideal for a server environment, whereas testing and unstable releases have more recent versions of software which usually contain some bugs. Ironically, Debian's unstable release is often more stable than many other distributions' final releases.

Zoneminder's even version numbers are stable releases.