These cumulative updates to Visual Studio 2015 include a variety of bug fixes and capability improvements.
The Visual C++ Redistributable Packages for Visual Studio 2015 Update 1 install run-time components of Visual C++ libraries. These components are required to run C++ applications that are developed using Visual Studio 2015 Update 1 and link dynamically to Visual C++ libraries. The packages can be used to run such applications on a computer even if it does not have Visual Studio 2015 installed. These packages also install run-time components of C Runtime (CRT), Standard C++, MFC, C++ AMP, and OpenMP libraries.
The Visual C++ Redistributable for Visual Studio 2015 Update 1 includes bug fixes to the runtime DLLs and also updated versions for
KB 2999226.
VS Release Notes
TFS Release Notes
VS Known Issues
System Requirements
Compatibility