title: What is "Upgrade from VC 7.1" property sheet?
body: <p>I'm porting a project from MSVS2005 to MSVS2010. I just loaded the solution in MSVS2010 and let the wizard convert the projects.</p>
  
  <p>I ran into the property manager and found these property sheets (top-to-bottom):</p>
  
  <ul>
  <li>Upgrade from VC 7.1</li>
  <li>Microsoft.Cpp.x64(or Win32).user</li>
  <li>Multi-byte Character Support (not editable)</li>
  <li>Dynamic Link to MFC (not editable)</li>
  </ul>
  
  <p>I understand the last three ones but I don't know what is the purpose of <strong>Upgrade from VC 7.1</strong>. Can someone give me a little explanation?</p>
  
  <hr>
  
  <p>P.S. I found C/C++, Preprocessor, Preprocessor Definitions = <strong>_VC80_UPGRADE=0x0710;%(PreprocessorDefinitions)</strong> in property page "Upgrade from VC 7.1" but in project properties I see <strong>NDEBUG;WIN32;_LIB;%(PreprocessorDefinitions)</strong>. What does all this mean? What is the <strong>_VC80_UPGRADE=0x0710</strong> macro?</p>