KF-DATE: The date is not in the expected format
This code shows up when an electronic invoice is validated. Here is what it means, why it fires, and what to change in the file.
Why this code appears
The issue date is not written as eight digits YYYYMMDD with format 102. An ISO-style date (2026-09-01) is refused by the CII XSD schema, before any business rule runs.
How to fix it
Write <udt:DateTimeString format="102">20260901</udt:DateTimeString>. The format attribute is mandatory and equals 102.
What it looks like in the file
These two snippets are replayed against our own checker on a complete invoice, every time the site is built. The first one raises this code, the second one does not.
What raises the code:
<udt:DateTimeString format="102">01/09/2026</udt:DateTimeString>What to write instead:
<udt:DateTimeString format="102">20260901</udt:DateTimeString>Where it happens
This check is ours, not a code from the standard: we do not cover enough of EN 16931 to borrow its numbers, and a misattributed official code would send you to fix the wrong field. It concerns BT-2.