bbPress 2.6.x: don't allow "bumped" topics to surface to the top.

bbpress-topic-ordering.php

<?php
/**
 * Order bbPress topic archives by post date (date created), not by last activity.
 *
 * This can be added either within a standalone plugin or to a theme's functions.php
 * file.
 *
 * @param array $args
 *
 * @return array
 */
add_filter( 'bbp_after_has_topics_parse_args', function( array $args ): array {
	// Normally bbPress sorts topics by last active (which is stored as meta data). Undo this.
	unset( $args['meta_key'], $args['meta_type'] );

	// Default ordering is DESC, so all we typically need to do here is switch to ordering
	// by post date (date created).
	$args['orderby'] = 'date';

	return $args;
} );