Peppol BIS Billing 3.0 · rule
UBL-DT-12
What does UBL-DT-12 mean? Format attribute should not be present
Why did my invoice fail UBL-DT-12?
The format attribute should not be present on date (or similar) elements in an EN 16931 UBL invoice. Dates are always exchanged in the fixed ISO format (YYYY-MM-DD), so a format attribute is redundant and outside the core model. Remove it and send the value in the standard format.
Official rule text
Format attribute should not be present
Common causes
- Generator adds format="YYYY-MM-DD" or a locale format hint to date elements
- Mapping from formats (e.g. CII with format="102") carried the attribute into UBL
How do I fix it?
<cbc:IssueDate>2026-07-19</cbc:IssueDate>
Related rules
UBL-DT-01 · UBL-DT-06 · UBL-DT-07 · UBL-DT-08 · UBL-DT-09 · UBL-DT-10 · UBL-DT-11 · UBL-DT-13
Check your invoice against this rule
Paste it into the live demo, or call POST /v1/validate. See the quickstart.