What it means
An invoice or credit note can refer to a contract (BT-12) through cac:ContractDocumentReference, and EN 16931 uses only the identifier (cbc:ID) inside it. This rule checks that there is no cbc:IssueDate there, the date the contract document was issued. It is not the invoice date (BT-2), which sits directly in the invoice.
Why it matters
This is a warning, so the file is still accepted. The standard has no field for the date of the contract, so the recipient's software has nowhere to store it and normally ignores it. Remove it to keep the file in line with the standard.
How to fix it
Clear the contract date in the contract section of your invoicing software and keep the contract number. Leave the invoice date as it is, because it is required. If the contract date is important to the buyer, add it to the invoice note. If you build the XML yourself, delete cbc:IssueDate from cac:ContractDocumentReference.
The rule as published
A UBL invoice should not include the ContractDocumentReference IssueDate 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-096 still fails, and which other rules do.