title: VSTO Outlook Add-In Ribbon not showing in Outlook 2007
body: <p>I have an Outlook add-in developed using VSTO Outlook 2010 template which has a ribbon. The ribbon xml is</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;customUI onLoad="Ribbon_Load" xmlns="http://schemas.microsoft.com/office/2006/01/customui"&gt;
      &lt;ribbon&gt;
          &lt;tabs&gt;
              &lt;tab idMso="TabAddIns"&gt;
                  &lt;group id="PluginGroup" label="the Collective"&gt;
                      &lt;button id="FolderSelector" onAction="FolderSelector_Click" screentip="Click to select forwarding folder" label="Folder Selector" showImage="false" /&gt;
                      &lt;labelControl id="label1" label="Current Folder :" screentip="Folder which all email will be forwarded" /&gt;
                      &lt;labelControl id="guiCurrrentChooserFolder" label="Please Select a folder" /&gt;
                  &lt;/group&gt;
              &lt;/tab&gt;
          &lt;/tabs&gt;
      &lt;/ribbon&gt;
  &lt;/customUI&gt;
  </code></pre>
  
  <p>This ribbon shows and functions properly in Outlook 2016. However, the ribbon does not show in Outlook 2007. Is this a compatibility issue? How can I modify this <code>xml</code> to support Outlook 2007 as well?</p>
  
  <p>Other than the UI, the functionality of the Add-In is working in both Outlook 2016 and Outlook 2007. I'm using Visual Studio 2015 to develop this.</p>