UBL-CR-665: Only an invoiced object reference may carry a scheme identifier

What it means

A UBL file can hold several additional document references (cac:AdditionalDocumentReference). Only a reference with document type code 130 is an invoiced object identifier (BT-18), for example a subscription number or a meter point, and only that one may state the scheme of its identifier (BT-18-1). This rule checks that every other reference, including one with no document type code, has no schemeID on its cbc:ID. A supporting document reference (BG-24, BT-122) is a plain identifier with no scheme.

Why it matters

This is a warning. A scheme on a supporting document reference has no meaning in EN 16931. It is worth fixing when you control the export, or when a recipient asks for a file with no warnings.

How to fix it

Open the references and attached documents on the invoice in your software. If the reference is a normal supporting document, such as a delivery note or a contract, clear the scheme or type field next to its number. If it is really an invoiced object, such as a subscription or a meter, enter it as an invoiced object reference. If you build the XML yourself, delete the schemeID attribute from cbc:ID in cac:AdditionalDocumentReference unless cbc:DocumentTypeCode is 130.

The rule as published

A UBL invoice should not include the AdditionalDocumentReference ID schemeID unless the DocumentTypeCode equals '130'

Where this rule applies