Parallax backgrounds not working after update

Hi,

All parallax image backgrounds have stopped working after the update. Cleared cache multiple times and I have also placed the code below in my child theme functions.php file:

function modify_jquery() {
if (!is_admin()) {
wp_deregister_script(‘jquery’);
wp_register_script(‘jquery’, ‘https://code.jquery.com/jquery-1.11.3.min.js’);
wp_enqueue_script(‘jquery’);
}
}
add_action(‘init’, ‘modify_jquery’);