app-catalog-ui/app_catalog/static/dashboard/project/app_catalog/retired_panel.html

<div>
    <div class="modal-header">
        <h3 class="modal-title">Retired</h3>
    </div>
    <div class="modal-body">
      The OpenStack App Catalog no longer supports this version of the Horizon plugin. Please contact your Cloud Administrator for an upgraded version.
    </div>
    <div class="modal-footer">
      <button class="btn btn-default" ng-click="cancel()">Close</button>
    </div>
</div>