In expressions of calendar dates
calendar year is, unless specified otherwise, represented by four digits. Calendar years are numbered in
ascending order according to the Gregorian calendar by values in the range [0000] to [9999]. Values in
the range [0000] through [1582] shall only be used by mutual agreement of the partners in information
interchange.
calendar month is represented by two digits. January is represented by [01], and subsequent calendar
months are numbered in ascending sequence.
calendar day of the month is represented by two digits. The first calendar day of any calendar month is
represented by [01] and subsequent calendar days of the same calendar month are numbered in
ascending sequence.
4.1.2.2 Complete representations
When the application identifies the need for a complete representation of a calendar date, it shall be one of
the numeric expressions as follows, where [YYYY] represents a calendar year, [MM] the ordinal number of a
calendar month within the calendar year, and [DD] the ordinal number of a calendar day within the calendar
month.
Basic format: YYYYMMDD Example: 19850412
Extended format: YYYY-MM-DD Example: 1985-04-12
4.1.2.3