the_modified_date() WordPress Function

function the_modified_date( $format = '', $before = '', $after = '', $echo = true ) {
	$the_modified_date = $before . get_the_modified_date( $format ) . $after;

	/**
	 * Filters the date a post was last modified for display.
	 *
	 * @since 2.1.0
	 *
	 * @param string|false $the_modified_date The last modified date or false if no post is found.
	 * @param string       $format            PHP date format.
	 * @param string       $before            HTML output before the date.
	 * @param string       $after             HTML output after the date.
	 */
	$the_modified_date = apply_filters( 'the_modified_date', $the_modified_date, $format, $before, $after );

	if ( $echo ) {
		echo $the_modified_date;
	} else {
		return $the_modified_date;
	}

}