How to resolve assembly conflict in Visual Studio 2013 web app project? - visual-studio-2013

Question

I have inherited a web app which reports the following assembly conflict when I try to build it under Visual Studio 2013;
There was a conflict between "System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" and "System.Web.Mvc, Version=4.0.0.1, Culture=neutral, PublicKeyToken=31bf3856ad364e35".
"System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" was chosen because it was primary and "System.Web.Mvc, Version=4.0.0.1, Culture=neutral, PublicKeyToken=31bf3856ad364e35" was not.
References which depend on "System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" [C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET MVC 4\Assemblies\System.Web.Mvc.dll].
C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET MVC 4\Assemblies\System.Web.Mvc.dll
Project file item includes which caused reference "C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET MVC 4\Assemblies\System.Web.Mvc.dll".
System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL
References which depend on "System.Web.Mvc, Version=4.0.0.1, Culture=neutral, PublicKeyToken=31bf3856ad364e35" [].
C:\Users\Administrator\Source\Repos\eRTQ\Software\web\ThirdPartyDll\MIM.Framework.Unity.dll
Project file item includes which caused reference "C:\Users\Administrator\Source\Repos\eRTQ\Software\web\ThirdPartyDll\MIM.Framework.Unity.dll".
MIM.Framework.Unity, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL
MIM.Core.ServiceHosts, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL
C:\Users\Administrator\Source\Repos\eRTQ\Software\web\ThirdPartyDll\Microsoft.Web.Mvc.FixedDisplayModes.dll
Project file item includes which caused reference "C:\Users\Administrator\Source\Repos\eRTQ\Software\web\ThirdPartyDll\Microsoft.Web.Mvc.FixedDisplayModes.dll".
Microsoft.Web.Mvc.FixedDisplayModes, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL
The Web.config contains this with respect to that assembly;
<compilation debug="true" targetFramework="4.5">
<assemblies>
<add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System.Web.Helpers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System.Web.Mvc, Version=4.0.0.1, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System.Web.WebPages, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</assemblies>
</compilation>
and
<dependentAssembly>
<assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35"/>
<bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.1"/>
</dependentAssembly>
I've tried removing and re-adding the assembly reference. That doesn't seem to change anything.
I can change the version in Web.config from '4.0.0.1' to '4.0.0.0', and that eliminates the warning, but is it the right thing to do?
Ideas?