title: What is <MvcProjectUpgradeChecked> Element in csproj file
body: <p>I have just opened my existing application in <code>VS 2015 RC</code> and after some automatic upgradations check, it added the following lines in the csproj file of the project.</p>
  
  <pre><code>&lt;MvcProjectUpgradeChecked&gt;true&lt;/MvcProjectUpgradeChecked&gt;
  &lt;FileUpgradeFlags&gt;
  &lt;/FileUpgradeFlags&gt;
  &lt;UpgradeBackupLocation&gt;
  &lt;/UpgradeBackupLocation&gt;
  &lt;OldToolsVersion&gt;4.0&lt;/OldToolsVersion&gt;
  </code></pre>
  
  <p></p>
  
  <p>I was wondering what does these line do? Can I check them in safely to the source control assuming that anyone else opening the solution can open it in some previous versions of Visual Studio ?</p>
  
  <p>I was unable to find anything on MSDN for this tag</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>I just opened the solution after csproj modifications in <code>Visual Studio 2013</code> and it opened without any issue, so this seems to be just a flag. But, nonetheless, can anybody share some definition for this?</p>