People look at ISO-8601 and think year-month-day looks great! But don’t realize that it also includes thing like —month-day (yes, you don’t need to include year

People look at ISO-8601 and think year-month-day looks great! But don’t realize that it also includes thing like —month-day (yes, you don’t need to include year to have a valid iso date!) year-week, year-day and lots of other things. So I would generally advise against accepting iso formatted dates and instead decree a single date format. https://en.m.wikipedia.org/wiki/ISO_8601 https://en.m.wikipedia.org/wiki/ISO_8601