title: Missing assemblies System.Net.Http.Primitives and System.Net.Http.Extensions.dll in build
body: <p>I am trying to build a legacy .net 4 web application and although the build succeeds when trying to visit the site I get </p>
  
  <pre><code>        Could not load file or assembly 'System.Net.Http.Primitives' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
  </code></pre>
  
  <p>or</p>
  
  <pre><code>        Could not load file or assembly 'System.Net.Http.Extensions' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
  </code></pre>
  
  <p>I can manually add these files from backups and the site works but how can I get the to be part of the build output?</p>
  
  <p>Nuget on the solution already includes "Microsoft.Net.Http.2.0.20710.0" and "System.Net.Http.2.0.20505.0" but neither of these include the missing dlls.</p>
  
  <p>This needs to work on a separate build server so having hard coded paths for random dlls is a no-no.</p>
  
  <p>The code is quite old and I cannot see any references anywhere in the code to either assembly. </p>
  
  <p>there is one other Dll missing compared with the backups but I am unsure it is related "System.Web.ApplicationServices.dll" as no amount of Google turns up any Nuget packages that could contain it.</p>