In-template Notification

include.liquid

<style>
  #tmp-notify {
    position:absolute;
    margin:20px;
    left:0;
    top:0;
    right:0;
    z-index:9999;
  }

  #tmp-notify div {
    text-align:center;
    background:#F9EDBE;
    border:1px solid #F0C36D;
    border-radius:5px;
    color:#222;
    font-family:Arial, sans-serif;
    font-size:13px;
    padding:12px;
  }

  #tmp-notify a {
    text-decoration:none;
    color:#1155CC;
    cursor:pointer;
  }
</style>

<script>
(function(){
  var msg = 'There is a newer version of this template. It is recommended that you update to the latest version.';
  var btn = 'Learn More';
  var url = 'http://google.com';
  
  if ($('body').hasClass('page_preview')) {
    var cnt = '<div id="tmp-notify"><div>' + msg + '  <a href="' + url + '" target="_blank">' + btn + '</a> | <a id="tmp-close">Dismiss</a></div></div>';
    $('body').prepend(cnt);
    $('#tmp-close').on('click', function () {
      $('#tmp-notify').remove();
    });
  }
})();
</script>

Just paste at the bottom of the page, edit the msg, btn and url variables and you're good to go.

msg = The text message.
btn = The link text.
url = Where to have the link go!

Leave btn & url blank to avoid having it appear.

Standard message warning of template deprecation:
"This template will be removed from the gallery on November 15, 2013 and support will be discontinued. Please consider using another template for your page."