BR-01: Add the specification identifier in CustomizationID

The short answer

BR-01 fails when the Invoice or CreditNote root has no cbc:CustomizationID, or has one with nothing in it. Add the element ahead of cbc:ProfileID and give it the Peppol BIS Billing 3.0 value: urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0.

This rule only asks for some text. Whether the text is the right identifier is a separate check, PEPPOL-EN16931-R004, and a missing identifier fails both.

What the rule checks

The rule looks at the cbc:CustomizationID that is a direct child of the document root and fails when it is absent or contains only whitespace. Any other text satisfies it: a document carrying the bare urn:cen.eu:en16931:2017 passes BR-01 and is reported by PEPPOL-EN16931-R004 alone.

Missing and empty behave slightly differently. The UBL schema treats cbc:CustomizationID as optional, so a document with no such element passes the XSD layer and reports BR-01 and PEPPOL-EN16931-R004. An element that is present but empty, or holds only whitespace, reports those two and also PEPPOL-EN16931-R008, the Peppol rule against empty elements.

Whitespace around a correct value is harmless here. A pretty-printed element with the identifier on its own line passes every layer.

How an integration ends up here

Possible causes, from the shape of the rule rather than from measured usage:

• The identifier is a configuration constant that was set for the invoice template but never for the credit note template.
• The serialiser drops elements whose source value is null, and the identifier is looked up per recipient or per profile from a table that has no row for this case.
• The same lookup returns an empty string, so the element is written with no content.
• The UBL export was built for a non-Peppol recipient and never carried a specification identifier.
• The integration fills in the identifier on the transport envelope and assumes the document itself does not need it.

How to fix it

1. Emit cbc:CustomizationID as a direct child of the Invoice or CreditNote root, before cbc:ProfileID.
2. Set it from a constant for the specification you produce. For Peppol BIS Billing 3.0 that is urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0.
3. Apply the same constant to credit notes; the element and the value are identical.
4. Leave cbc:ProfileID as the business process identifier. The two are different fields and one cannot stand in for the other.

Validate your corrected invoice

Before and after

These are fragments, not complete documents. The complete synthetic documents they come from are linked below.

Start of the failing invoice: the root goes straight to the profile identifier

<!-- first children of the Invoice root; there is no cbc:CustomizationID -->
<cbc:ProfileID>urn:fdc:peppol.eu:2017:poacc:billing:01:1.0</cbc:ProfileID>
<cbc:ID>EXAMPLE-INV-001</cbc:ID>
<cbc:IssueDate>2026-09-08</cbc:IssueDate>
<!-- rest of the document omitted -->

Start of the corrected invoice: the specification identifier comes first

<cbc:CustomizationID>urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0</cbc:CustomizationID>
<cbc:ProfileID>urn:fdc:peppol.eu:2017:poacc:billing:01:1.0</cbc:ProfileID>
<cbc:ID>EXAMPLE-INV-001</cbc:ID>
<cbc:IssueDate>2026-09-08</cbc:IssueDate>
<!-- rest of the document omitted -->

The corrected invoice has the cbc:CustomizationID element and the failing one does not; nothing else differs. The failing document also reports PEPPOL-EN16931-R004, which requires the identifier to begin with the Peppol BIS Billing 3.0 value and cannot be met by an identifier that is not there. Adding the element with that value clears both.

Where it applies

• Applies to UBL Invoice and CreditNote alike. The recorded credit note without the element reports the same two rules.
• The value given here is the one for Peppol BIS Billing 3.0, which is the scope of this reference. Other specifications built on EN 16931 have their own identifiers and their own rules for them.
• The identifier states which specification the document claims to follow. It says nothing about whether the receiver is registered to accept that document type.

Related rules

• PEPPOL-EN16931-R004 checks that the identifier is the Peppol BIS Billing 3.0 one
• PEPPOL-EN16931-R001 is the matching presence check for the business process in ProfileID
• PEPPOL-EN16931-R008 is reported as well when the element is present but empty
• BR-02 is the same kind of check for the invoice number
• Browse every rule in the reference
• Background: Understanding EN 16931 validation errors

Scope and source

Written for Peppol BIS Billing 3.0.21 (May 2026), EN 16931 1.3.16, as applied to UBL 2.1 Invoice and CreditNote documents. Other profiles, syntaxes and releases can define this identifier differently. Guidance version 2026-09-24.1: source checked 2026-09-24, explanation last updated 2026-09-20.

The official definition of BR-01 carries the normative wording and test. This page is our explanation of it, not a copy.

Guidance does not change the engine verdict. Fixing this finding does not mean the document passes every layer, and validation does not certify legal or tax compliance or transmit a document over Peppol.