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Warning

UBL-CR-544: A line's document reference should not carry an attachment of its own

In short

Warning: worth checking.

UBL-CR-544 means an invoice line has an attachment inside its document reference, and EN 16931 has no place for that. Remove it from the line and attach the document to the invoice as a whole.

On this page

What it means

The rule checks every line of the invoice, or of the credit note, for a document reference that contains an attachment (cac:Attachment). The test only checks whether the element is there, not what it holds.

Why it matters

This is a warning. It is worth fixing whenever the recipient needs that document, for example a timesheet or a delivery note.

How to fix it

Remove the attachment from the line. Attach the document to the invoice as a whole in your invoicing software, as a supporting document. If you build the XML yourself, delete cac:Attachment under cac:DocumentReference in the line (cac:InvoiceLine or cac:CreditNoteLine), and add the file under cac:AdditionalDocumentReference at the top level of the invoice.

Once the file is corrected, check it again for free: Validate an invoice against EN 16931

Or fix the invoice in a form and download the corrected file, for 1 credit: Fix a rejected e-invoice

The rule as published

A UBL invoice should not include the InvoiceLine DocumentReference Attachment

Where this rule applies

Rule set Version
EN 16931 (UBL) 1.3.17
EN 16931 (UBL credit note) 1.3.17
XRechnung 3.0 (UBL) 3.0.2
XRechnung 3.0 (UBL credit note) 3.0.2
Peppol BIS Billing 3.0 (invoice) 2026.5
Peppol BIS Billing 3.0 (credit note) 2026.5
SI-UBL 2.0 / NLCIUS (invoice) 2.0.3.13
SI-UBL 2.0 / NLCIUS (credit note) 2.0.3.13
France CTC (UBL invoice) 1.4.0-04
France CTC (UBL credit note) 1.4.0-04
CIUS-RO UBL Invoice 1.0.9 1.0.9
CIUS-RO UBL Credit Note 1.0.9 1.0.9
Rule text from phive-rules 4.6.4.

Check your file

Drop your e-invoice to see whether UBL-CR-544 still fails, and which other rules do.

Updated 6 November 2026