public static function isoDate(\DateTimeInterface $date)
    {
        $date = clone $date;
        $date = $date->setTimezone(new \DateTimeZone('UTC'));

        return str_replace('+00:00', 'Z', $date->format('c'));
    }
public static function isoDate(\DateTimeInterface $date)
    {
        $date = clone $date;
        $date = $date->setTimezone(new \DateTimeZone('UTC'));

        return str_replace('+00:00', 'Z', $date->format('c'));
    }
public static function isoDate ( \ DateTimeInterface $ date ) { $ date = clone $ date ; $ date = $ date -> setTimezone ( new \ DateTimeZone ( 'UTC' ) ) ; return str_replace ( '+00:00' , 'Z' , $ date -> format ( 'c' ) ) ; }
Generate ISO 8601 compliant date string in UTC time zone

@param \DateTimeInterface $date The date value to convert

@return string
Generate ISO 8601 compliant date string in UTC time zone