Errors after updating to WordPress 3.6 (with solution)

If, like me, you’re getting PHP ‘Strict’ warnings from this plugin after updating to WordPress 3.6, here’s what I did to solve the problem:

In the plugin folder, in the file ‘post-types-order.php’, on line 311, replace that entire class block with the following:

class Post_Types_Order_Walker extends Walker
    {

        var $db_fields = array ('parent' => 'post_parent', 'id' => 'ID');

        function start_lvl(&$output, $depth = 0, $args = array()) {
            $indent = str_repeat("\t", $depth);
            $output .= "\n$indent<ul class='children'>\n";
        }

        function end_lvl(&$output, $depth = 0, $args = array()) {
            $indent = str_repeat("\t", $depth);
            $output .= "$indent</ul>\n";
        }

        function start_el(&$output, $object, $depth = 0, $args = array(), $current_object_id = 0) {
            if ( $depth )
                $indent = str_repeat("\t", $depth);
            else
                $indent = '';

            extract($args, EXTR_SKIP);

            $output .= $indent . '<li id="item_'.$object->ID.'"><span>'.apply_filters( 'the_title', $object->post_title, $object->ID ).'</span>';
        }

        function end_el(&$output, $object, $depth = 0, $args = array()) {
            $output .= "</li>\n";
        }

    }

http://wordpress.org/plugins/post-types-order/