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Warning

UBL-CR-134: A project reference should not have a UUID

In short

Warning: worth checking.

UBL-CR-134 means the project reference in your UBL file has a UUID (cbc:UUID), which EN 16931 does not use. Keep the project reference itself and remove the UUID.

On this page

What it means

The project reference (BT-11) is cbc:ID inside cac:ProjectReference. This rule checks that a document-level cac:ProjectReference in a UBL invoice or credit note does not also contain cbc:UUID. It checks for the presence of that element, not the format of its value.

Why it matters

EN 16931 uses the project reference (BT-11), not a separate UUID element beside it.

How to fix it

Keep the project reference in cac:ProjectReference/cbc:ID and remove cac:ProjectReference/cbc:UUID. If the buyer needs the UUID, agree with them where it should go, for example in an invoice note. Export the corrected file and check it again.

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 ProjectReference UUID

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-134 still fails, and which other rules do.

Updated 6 November 2026