Open Visual Studio 2009 Solution in Visual Studio 2013 without Upgrading : In short: **I need to open an application originally built in VS09 in VS13 without upgrading the project since the overall project architecture must remain the same for when I check it back into source control.**

Details: I need to open a Visual Studio solution (.sln) inside **Visual Studio 2013**. The solution in question was originally developed in Visual Studio 2009, so when I try to open said solution in Visual Studio 2013, I am shown a prompt with the projects within the solution checkmarked, with the message:

* These projects are either or supported or need project behavior impacting modifications to open in this version of Visual Studio. Projects no displayed either require no changes or will automatically be modified such that behavior is not impacted. Visual Studio will automatically make functional changes to the following projects in order to open them. You will not be able to open these projects in the version of Visual Studio in which they were originally created.*

My attempt at a fix was to just upgrade the solution and hope for the best. This is successful, but after building and attempting to run the main project, I see the following build error:

* The type 'Microsoft.Web.Services3.WebServicesClientProtocol' is defined in an assembly that is not referenced. You must add a reference to assembly 'Microsoft.Web.Services3, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. *

I then tried both commenting out the references to this assembly *and* adding in the missing reference. Okay, so then I rebuilt the solution and attempted to run. Same error, but for a different assembly. Repeat fix, same error for different assembly. This pattern continues and continues, and at this point I realize this is unacceptable anyway, because when I make a change to this solution, I need to check it back into source control. When others open it, they may be opening it in VS09, and therefore this “upgraded” version is inconsistent with the version the business uses. I need to open the solution originally build in VS 2009 in VS 2013 (can't work around this, needs to be VS13). If it helps, I'm using *64 bit Visual Studio 2013 Ultimate.*

Any help or guidance will be greatly appreciated!