Peppol BIS Billing 3.0 · rule

UBL-CR-125

Layer en16931·Checked against Peppol BIS Billing 3.0 2026.5

What does UBL-CR-125 mean? A UBL invoice should not include the AdditionalDocumentReference Attachment External MimeCode

Why did my invoice fail UBL-CR-125?

The invoice should not contain the element cac:AdditionalDocumentReference/cac:Attachment/cac:ExternalReference/cbc:MimeCode, i.e. a MIME code on an externally referenced attachment. This is one of the EN 16931 "cardinality restriction" (UBL-CR) warnings: the UBL 2.1 schema allows the element, but it maps to no business term in the EN 16931 core invoice model, so a compliant core invoice must leave it out. In EN 16931 a MIME code is only defined for the embedded binary attachment (an attribute of BT-125), not for the external reference, which carries only the URI (BT-124). Receivers may ignore or reject data carried in such elements, so remove it or move the information to the supported business term.

Official rule text

A UBL invoice should not include the AdditionalDocumentReference Attachment External MimeCode

Common causes

Your invoice generator emits the full UBL 2.1 structure and populates cbc:MimeCode even though EN 16931 does not use it
Mapping from an internal/ERP data model copies every available field into the UBL output instead of only the EN 16931 business terms
A template or example invoice from a non-EN 16931 UBL context (e.g. generic UBL samples) was reused without stripping unsupported elements

How do I fix it?

<cac:Attachment>
  <cbc:EmbeddedDocumentBinaryObject mimeCode="application/pdf" filename="invoice.pdf">JVBERi0xLjQ=</cbc:EmbeddedDocumentBinaryObject>
</cac:Attachment>

Check your invoice against this rule

Paste it into the live demo, or call POST /v1/validate. See the quickstart.