get_lastcommentmodified( string $timezone = 'server' ): string|false

410function get_lastcommentmodified( $timezone = 'server' ) {411	global $wpdb;412 413	$timezone = strtolower( $timezone );414	$key      = "lastcommentmodified:$timezone";415 416	$comment_modified_date = wp_cache_get( $key, 'timeinfo' );417	if ( false !== $comment_modified_date ) {418		return $comment_modified_date;419	}420 421	switch ( $timezone ) {422		case 'gmt':423			$comment_modified_date = $wpdb->get_var( "SELECT comment_date_gmt FROM $wpdb->comments WHERE comment_approved = '1' ORDER BY comment_date_gmt DESC LIMIT 1" );424			break;425		case 'blog':426			$comment_modified_date = $wpdb->get_var( "SELECT comment_date FROM $wpdb->comments WHERE comment_approved = '1' ORDER BY comment_date_gmt DESC LIMIT 1" );427			break;428		case 'server':429			$add_seconds_server = gmdate( 'Z' );430 431			$comment_modified_date = $wpdb->get_var( $wpdb->prepare( "SELECT DATE_ADD(comment_date_gmt, INTERVAL %s SECOND) FROM $wpdb->comments WHERE comment_approved = '1' ORDER BY comment_date_gmt DESC LIMIT 1", $add_seconds_server ) );432			break;433	}434 435	if ( $comment_modified_date ) {436		wp_cache_set( $key, $comment_modified_date, 'timeinfo' );437 438		return $comment_modified_date;439	}440 441	return false;442}