title: Is there any guidance on converting existing .NET class libraries to portable libraries?
body: <p>I have some class libraries with a non-trivial amount of existing code. The class libraries currently target .NET 4.0. Is there any guidance on how to convert these libraries to be portable libraries? From looking at the .csproj, it doesn't appear that there are a lot of differences:</p>
  
  <pre><code>&lt;Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" /&gt;
  </code></pre>
  
  <p>and</p>
  
  <pre><code>&lt;ProjectTypeGuids&gt;{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}&lt;/ProjectTypeGuids&gt;
  </code></pre>
  
  <p>Is it a good or bad idea to try converting an existing class library to be a portable library?</p>