&null;, in which case the default timezone will be used, as specified in the ini setting date.timezone or through the function date_default_timezone_set and as returned by date_default_timezone_get. An IntlTimeZone, which will be used directly. A DateTimeZone. Its identifier will be extracted and an ICU timezone object will be created; the timezone will be backed by ICUʼs database, not PHPʼs. A string, which should be a valid ICU timezone identifier. See IntlTimeZone::createTimeZoneIDEnumeration. Raw offsets such as "GMT+08:30" are also accepted.