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Warning

UBL-CR-020: The purchase order reference should not have a customer reference

In short

Warning: worth checking.

UBL-CR-020 means the document-level purchase order reference contains a customer reference (cbc:CustomerReference), which EN 16931 does not use. Remove this element. Move its value to the buyer reference (BT-10) or purchase order number (BT-13) only if that field matches what the value means.

On this page

What it means

The rule checks that the document-level cac:OrderReference has no cbc:CustomerReference. EN 16931 has two fields that look similar: the buyer reference (BT-10) in cbc:BuyerReference at the top of the file, and the purchase order number (BT-13) in cac:OrderReference/cbc:ID.

Why it matters

EN 16931 uses separate fields for the buyer reference (BT-10) and purchase order number (BT-13), rather than cbc:CustomerReference within the order reference.

How to fix it

Decide what the value is. If the buyer gave it as their reference for the invoice, for example a department, a contact or a Leitweg-ID, put it in the buyer reference (BT-10). If it is the number of their purchase order, put it in cbc:ID inside cac:OrderReference. Then delete cbc:CustomerReference from the document-level cac:OrderReference, export again and 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 OrderReference CustomerReference

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-020 still fails, and which other rules do.

Updated 6 November 2026