What is "Platform Toolset" setting in visual studio project

It is the version of all the tools used to compile and link your project.

Moreless it is a version of toolchain that is used to build your project. So depends on version you have selected, different compiler, linker (etc) versions are used. If you select toolset version that was released with VS2017 (v141), MSBuild will use tools from this toolset do build your project.

It is nicely described under link provided by: YoavKlein. "The platform toolset consists of the C++ compiler (cl.exe) and linker (link.exe), along with the C/C++ standard libraries. Since Visual Studio 2015, the major version of the toolset has remained at 14, which means that projects compiled with Visual Studio 2019 or Visual Studio 2017 are ABI-backwards-compatible with projects compiled with Visual Studio 2015. The minor version has updated by 1 for each version since Visual Studio 2015: Visual Studio 2015: v140 Visual Studio 2017: v141 Visual Studio 2019: v142"

So there is no difference in ABI if the major version is same (but in your case you ask about change from v110 to v100 so the compatibility may be broken), but it may happen that f.e. compiler provided with older version of toolset does not implement some features of the new or incomming c++ standard etc.

It is an MSBuild property that controls the specific version of the platform toolset that you want to use.

More info here: http://msdn.microsoft.com/en-us/library/windows/hardware/hh454232%28v=vs.85%29.aspx

Most likely you want to use the last stable Windows SDK. You can check the toolset that you are using looking at your Visual Studio project file (.vcxproj), looking for this XML entry:

<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'"
      Label="Configuration">
  <ConfigurationType>Driver</ConfigurationType>
  <DriverType>KMDF</DriverType>
  <PlatformToolset>WindowsKernelModeDriver8.1</PlatformToolset>
</PropertyGroup>