function bbp_approved_unapproved_topic_update_forum_reply_count( $topic_id = 0 ) {

	// Bail early if we don't have a topic id.
	if ( empty( $topic_id ) ) {
		return;
	}

	// Get the topic's replies.
	$count = bbp_get_public_child_count( $topic_id, bbp_get_reply_post_type() );

	// If we're unapproving, set count to negative.
	if ( 'bbp_unapproved_topic' === current_filter() ) {
		$count = -$count;
	}

	// Bump up or down
	bbp_bump_forum_reply_count( bbp_get_topic_forum_id( $topic_id ), $count );
}