What it means
The rule warns if cac:AccountingCustomerParty/cac:Party in a UBL invoice or credit note contains cac:Language. In UBL it names a language the buyer uses, as a code, a name or a locale. EN 16931 has no business term for the buyer's language.
Why it matters
EN 16931 does not include a buyer language field. This warning concerns cac:Language in the buyer's party, not the language of the invoice text.
How to fix it
Delete the whole cac:Language block from cac:AccountingCustomerParty/cac:Party. If your invoicing software adds it, ask its supplier to exclude this block from the e-invoice export. 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 AccountingCustomerParty Party Language 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 |
Check your file
Drop your e-invoice to see whether UBL-CR-209 still fails, and which other rules do.
Related rules
- UBL-CR-210 The buyer's address should not have an address ID
- UBL-CR-211 The buyer's address should not have an address type code
- UBL-CR-212 The buyer's address should not have an address format code
- UBL-CR-213 The buyer's address should not have a separate PO box field
- UBL-CR-214 The buyer's address should not have a separate floor field
- UBL-CR-215 The buyer's address should not have a separate room field