bbPress.org

date order:

put this in your functions fil :

function rew_date_topic_order( $args ) {
                $args['orderby']='date';
                $args['order']='DESC';  //change to ASC to put oldest at top
                return $args;
}
add_filter('bbp_before_has_topics_parse_args','rew_date_topic_order');

Functions files and child themes – explained !