Now that Quick Cache is no longer being maintained, a deprecated notice appears in the Options panel:

2015-03-13_17-24-52

If you choose to continue using Quick Cache and you want to disable the deprecated notice, you can add the following code to an MU-Plugin or to your theme's functions.php file:

add_filter('quick_cache_show_deprecated_notice', '__quick_cache_show_deprecated_notice', 10, 0);
function __quick_cache_show_deprecated_notice() {
    return FALSE; // Disable the deprecated notice
}