URI: 

       Title: How to switch to NixOS development version
       Author: Solène
       Date: 17 May 2021
       Tags: nixos
       Description: 
       
       This short guide will explain you how to switch a NixOS installation to
       the unstable channel, understand the development version.
       
       ```command example
       nix-channel --add https://channels.nixos.org/nixos-unstable nixos
       ```
       
       You will have to reload the channel list using the command "nix-channel
       --update" and then you can upgrade your system using "nixos-rebuild
       switch".
       
       If you have issues, you can rollback using "nix-channel --rollback"
       that will set the channels list to the last state before "--update".
       
  HTML Nix channels wiki page
  HTML Nix-channel man page