title: Running .NET 4.0 app with reference to 2.0 library on machine with only 4.0 framework
body: <p>This would be a real pain to try to duplicate, so I'm hoping someone has a quick answer...</p>
  
  <p>Suppose I have a .NET 4.0 application, with a reference to a .NET 2.0 library (SharpZipLib in this case). This of course works fine on a normal machine with .NET 2.0 and 4.0 installed.</p>
  
  <p>If the server running this application has only .NET 4.0 and not 2.0 (or 3.0/3.5 etc.), what do I need to do to allow the .NET 2.0 library to run properly?</p>
  
  <p>From what I've read, it looks like I may be able to put in a config setting for <code>supportedRuntime</code>, but I'm not quite understanding what exactly that does.</p>
  
  <p>Will a config setting work, or would only .NET 4.0 libraries function in this environment?</p>
  
  <p>(This is a hypothetical environment - I don't plan on ever having my own servers with 4.0 and not 2.0, but if someone is crazy enough to do it, I want to be able to support them).</p>
  
  <p>Thanks</p>