Currently, UCI does not accept 2, 4, or 6 digit dates while you could enter 2, 4, 6, or 8 digits in the date field in web client interface.
As with the web interface, the behavior described below makes it easier to use UCI.
Title : Working with Calendar Dates and Times
URL : https://docs.microsoft.com/ja-jp/dynamics365/business-central/ui-enter-date-ranges#digit-patterns??

In a date field you can enter two, four, six, or eight digits:
If you enter only two digits, this is interpreted as the day, and it will add the month and the year of the work date.
If you enter four digits, this is interpreted as the day and the month, and it will add the year of the work date. The order of the day and month is determined by your region settings. Even if your region settings have the year before the day and month, four digits are interpreted as the day and month.
If the date you want to enter is in the range 01/01/1930 through 12/31/2029, you can enter the year with two digits; otherwise, enter the year with four digits.
Category: General



The new UCI Date Field isn't as forgiving as the old Date Fields, You use to be able to paste in a lot of date values as well, and CRM would auto correct it to the correct format. This was a nice feature I used a lot, and has also disappeared. Like I could paste in 1/1/20 and it would correct it to 1/1/2020 but not it generally just errors out in the new UCI.

Category: General