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Warning

UBL-CR-531: A line should not carry its own billing reference

In short

Warning: worth checking.

UBL-CR-531 means an invoice or credit note line contains a billing reference (cac:BillingReference), which EN 16931 does not use on a line. It is a warning; remove the line-level reference and put any preceding invoice references at document level, then recheck the file.

On this page

What it means

A reference to an earlier invoice belongs at document level, as a preceding invoice reference (BG-3) with the earlier invoice number (BT-25) and optionally its date (BT-26). This rule warns when any cac:InvoiceLine or cac:CreditNoteLine contains cac:BillingReference. It does not limit the number of document-level preceding invoice references.

Why it matters

EN 16931 does not use billing references on invoice or credit note lines.

How to fix it

In your invoicing software, enter any preceding invoice references at the level of the whole document, not on a line. In the XML, delete cac:BillingReference from cac:InvoiceLine (cac:CreditNoteLine in a credit note) and keep any relevant cac:BillingReference elements directly under the invoice or credit note. Recheck the file.

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 BillingReference

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-531 still fails, and which other rules do.

Updated 6 November 2026