NixOS is a Linux distribution with a unique approach to package and configuration management. Built on top of the Nix package manager, it is completely declarative, makes upgrading systems reliable, and has many other advantages. NixOS 14.12 aka “Caterpillar” which is the third stable release branch was released late in December last year. This release comes bundled with Linux 3.14, systemd 217, Glibc 2.20, KDE 4.14.1, and much more. See the release notes for details.