title: Could not load file or assembly 'System.Net.Http, Version=4.2.0.0, Culture=neutral on IIS
body: <p>I started updating some nuget packages and started getting these warnings on build with a conflict for System.Net.Http. As suggested here:</p>
  
  <p><a href="https://stackoverflow.com/questions/47570912/strange-issue-with-system-net-http-4-2-0-0-not-found/48862675#48862675">Strange issue with System.Net.Http 4.2.0.0 not found</a></p>
  
  <p>I replaced all references to System.Net.Http to use the nuget version, instead of the one bundled with Visual Studio. I then changed all redirect bindings (app.configs and web.configs) as suggested everywhere and I got things working locally. But..</p>
  
  <p>When I deploy to our test server I still get the error </p>
  
  <pre><code>Could not load file or assembly 'System.Net.Http, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' 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´m using net 4.7.0 and Visual Studio 2017</p>
  
  <p>I searched all my configs for a ref to Version 4.2.0.0 but no hits. Why does the IIS think it needs this one?</p>
  
  <p>My nuget version of the System.Net.Http is 4.3.4 but the actual web.config has these lines</p>
  
  <pre><code>&lt;dependentAssembly&gt;
     &lt;assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/&gt;
     &lt;bindingRedirect oldVersion="0.0.0.0-4.1.1.3" newVersion="4.1.1.3"/&gt;
  &lt;/dependentAssembly&gt; 
  </code></pre>
  
  <p>Again I can build and run it locally but my server reports the error.</p>
  
  <p>UPDATE: I tried adding this on my servers web.config</p>
  
  <pre><code> &lt;dependentAssembly&gt;
      &lt;assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" /&gt;
      &lt;bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.1.1.3" /&gt;
    &lt;/dependentAssembly&gt;
  </code></pre>
  
  <p>That makes the error go away! But I still dont get why i need to do this? Like why do my server think it needs to use 4.2.0?</p>