CakePOWER allows you to add a virtual version name to all your assets:
// app/Config/core.php Configure::write('Asset.version', '1.0.3');
Every assets url created through CakePHP helpers will be postfixed with that version string:
<script src="/js/foo.js?v=1.0.3" /> <link href="/css/foo.css?v=1.0.3" />
You should manually change version’s string whenever you upload new version of your assets forcing all clients to download new copy of libraries, stylesheets, images, etc!