What it means
The rule looks at the item on every invoice line (or credit note line) in a UBL file. It warns when the item's VAT details (cac:ClassifiedTaxCategory) contain a cbc:TaxExemptionReason, a written reason why no VAT is charged. The VAT exemption reason text (BT-120) belongs in a VAT breakdown entry (BG-23), not in the line's classified tax category. This rule does not check whether a reason is present or required in the breakdown.
Why it matters
EN 16931 does not use exemption reason text within a line's classified tax category.
How to fix it
Check the export mapping for the exemption reason text in your invoicing software. If you need to include the text, such as Reverse charge or Intra-community supply, put it in the matching VAT breakdown entry. If you build the XML yourself, use cbc:TaxExemptionReason in cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory for that entry. Then delete it from cac:ClassifiedTaxCategory under cac:InvoiceLine/cac:Item (cac:CreditNoteLine in a credit note).
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 Item ClassifiedTaxCategory TaxExemptionReason 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-601 still fails, and which other rules do.
Related rules
- UBL-CR-602 A line's VAT category should not carry a tier range
- UBL-CR-603 A line's VAT category should not carry a tier rate
- UBL-CR-604 Line VAT category should not have a tax scheme name
- UBL-CR-605 Line VAT category should not have a tax type code
- UBL-CR-606 Line VAT category should not have a currency code
- UBL-CR-607 Line VAT category should not have a jurisdiction address