This is the version of MSBuild packaged with Visual Studio 2017 (build 26206.00) and with the dotnet CLI 1.0.0.
Release notes are available at https://docs.microsoft.com/en-us/visualstudio/msbuild/what-s-new-in-msbuild-15-0.
Installers are available as part of:
- Visual Studio 2017 (for Windows)
- Build Tools for Visual Studio 2017 (for Windows)
- .NET Core Sdk (for Windows, macOS, and Linux)