get_lastpostmodified( string $timezone = 'server', string $post_type = 'any' )

function get_lastpostmodified( $timezone = 'server', $post_type = 'any' ) {
	/**
	 * Pre-filter the return value of get_lastpostmodified() before the query is run.
	 *
	 * @since WP-4.4.0
	 *
	 * @param string $lastpostmodified Date the last post was modified.
	 *                                 Returning anything other than false will short-circuit the function.
	 * @param string $timezone         Location to use for getting the post modified date.
	 *                                 See get_lastpostdate() for accepted `$timezone` values.
	 * @param string $post_type        The post type to check.
	 */
	$lastpostmodified = apply_filters( 'pre_get_lastpostmodified', false, $timezone, $post_type );
	if ( false !== $lastpostmodified ) {
		return $lastpostmodified;
	}

	$lastpostmodified = _get_last_post_time( $timezone, 'modified', $post_type );

	$lastpostdate = get_lastpostdate($timezone);
	if ( $lastpostdate > $lastpostmodified ) {
		$lastpostmodified = $lastpostdate;
	}

	/**
	 * Filters the date the last post was modified.
	 *
	 * @since WP-2.3.0
	 *
	 * @param string $lastpostmodified Date the last post was modified.
	 * @param string $timezone         Location to use for getting the post modified date.
	 *                                 See get_lastpostdate() for accepted `$timezone` values.
	 */
	return apply_filters( 'get_lastpostmodified', $lastpostmodified, $timezone );
}