Reference

BR-21 Invoice line identifier is required

Each Invoice line (BG-25) shall have an Invoice line identifier (BT-126) that is unique within the invoice.

This is an EN 16931 core rule. The line identifier lets credit notes, disputes and corrections refer to one specific line. BR-21 only checks that the value is filled, not that it is unique. The error usually comes from an export that writes an empty line number, for example for text or subtotal lines taken over from a PDF.

Solution

Give every cac:InvoiceLine a cbc:ID value, for example 1, 2, 3, ensuring no line is left without an identifier.

Quick actions

Validate XML Convert invoice

Valid Examples

BT-126 = 1 on the first line, BT-126 = 2 on the second line

Invalid Examples

A cac:InvoiceLine with an empty cbc:ID (<cbc:ID></cbc:ID>), or a CII line with an empty ram:AssociatedDocumentLineDocument/ram:LineID; a missing cbc:ID in UBL is already an XML schema error

Code Examples

Valid XML

<cac:InvoiceLine>
  <cbc:ID>1</cbc:ID>
  <cbc:LineExtensionAmount currencyID="EUR">100.00</cbc:LineExtensionAmount>
</cac:InvoiceLine>

Invalid XML

<cac:InvoiceLine>
  <cbc:ID></cbc:ID>
  <cbc:LineExtensionAmount currencyID="EUR">100.00</cbc:LineExtensionAmount>
</cac:InvoiceLine>

Affected Fields

BT-126 Invoice line identifier

Validation Tools

Official KoSIT Validator

Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.

Convert PDF to XRechnung

Find validation errors during conversion and review each correction.