title: Office 365, outlook add-in icon does not update
body: <p>Developing an office 365, outlook add-in. Changed the add-in icon (Basically just replaced the old icons with new one. Icons have the same name.). Icon comes up fine on OWA but on Outlook 2016 add-in still, shows the old icon. </p>
  
  <p>Troubleshooting steps till now :</p>
  
  <ul>
  <li>Uninstall reinstall add-in => no effect.</li>
  <li>Uninstall add-in, restart Outlook 2016, reinstall add-in => no effect.</li>
  <li>Reset customizations from 'Customize Ribbon' option inside 'Outlook Options' => no effect.</li>
  <li>Restarted server => no effect</li>
  </ul>
  
  <p>validate-office-addin shows 'manifest.xml' as valid.</p>