The day of the month (QDAY) is used to indicate the day of the month on the system. This value must be a valid day of the month or a valid day of the year (if you are using the Julian date format).
You can change the day of the month to reflect the current day of the month in your country or location. If you change QDAY, you also change the value for QDATE. A change to this value takes place immediately.