Dart SDK and Dartium 1.21.0 Chocolatey Packages for Windows

Chocolatey is a package manager for Windows similar to Linux's apt-get, based on Microsoft's Nuget tool and Powershell scripting language. It works from the command-line and from a WPF GUI interface.

You can install unmoderated versions by specifiying the install version during installation.
Chocolatey has also been updated with versions 1.21.0
Command line installation:

choco uninstall dart-sdk

choco install -y dart-sdk  -version 1.21.0

To verify you have the right version on your path.

dart --version
Dart VM version: 1.21.0 (Thu Dec 07 06:52:21 2016) on "windows_x64"

Command line installation:

choco uninstall dartium

choco install -y dartium  -version 1.21.0