title: Can I build an "old school" PCL with DNX/DNU?
body: <p>In <a href="http://nodatime.org">Noda Time</a> 1.3.1, our <a href="https://github.com/nodatime/nodatime/blob/1.3.x/src/NodaTime/NodaTime.csproj">.csproj</a> file referred to Profile 328 and our <a href="https://github.com/nodatime/nodatime/blob/1.3.x/src/NodaTime/NodaTime.nuspec">.nuspec</a> file put the results in</p>
  
  <pre><code>lib\portable-net4+sl5+netcore45+wpa81+wp8+MonoAndroid1+MonoTouch1+XamariniOS1
  </code></pre>
  
  <p>For Noda Time 2.0, I've moved everything over to DNX/DNU (soon to be dotnet cli, of course). However, we now want to build a regularly-updated package containing the latest time zone information from <a href="https://www.iana.org/time-zones">IANA</a>. We'll build one version of that with a dependency on Noda Time 1.3.1, and another version with a dependency on Noda Time 2.0.0.</p>
  
  <p>I would <em>like</em> to do all of this still within DNX/DNU, but it's unclear to me whether there's any way of telling DNX/DNU about this target framework. Note that I want to make this available to all current users of 1.3.1, and it also depends on 1.3.1, so I believe the set of target frameworks basically needs to be identical.</p>
  
  <p>I've tried frameworks of:</p>
  
  <ul>
  <li>portable-net40+sl5+win8+wpa81+wp8 (which I expected to have the best chance of working based on the <a href="https://docs.nuget.org/create/targetframeworks">Nuget documentation</a>)</li>
  <li>portable-net4+sl5+netcore45+wpa81+wp8+MonoAndroid1+MonoTouch1+XamariniOS1</li>
  <li>Profile328 </li>
  </ul>
  
  <p>In every case, <code>dnu restore</code> shows an error of this form:</p>
  
  <blockquote>
    <p>"portable-net40+sl5+win8+wpa81+wp8" is an unsupported framework.</p>
  </blockquote>
  
  <p>I have a horrible suspicion that this basically isn't a supported use case, and that I'll need to stick to a regular csproj file for this particular part, but I thought it worth asking to see if I'm missing something.</p>