title: Cannot install nuget package unity 2
body: <p>I need to downgrade my app from 4.5 to 3.5 and i had unity 3 installed. Now i cannot install unity 2.1 from nuget, because of this error:</p>
  
  <pre><code>PM&gt; Install-Package Unity -Version 2.1.505.2
  The source at nuget.org [https://www.nuget.org/api/v2/] is unreachable. Falling back to NuGet Local Cache at C:\Users\voskresenskiy\AppData\Local\NuGet\Cache
  Install-Package : Unable to find version '2.1.505.2' of package 'Unity'.
  At line:1 char:16
  + Install-Package &lt;&lt;&lt;&lt;  Unity -Version 2.1.505.2
      + CategoryInfo          : NotSpecified: (:) [Install-Package], InvalidOperationException
      + FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand
  </code></pre>
  
  <p>What am i doing wrong? I'll be gratefull for any help</p>