UBL-SR-08:Quantity missing unit code
Fix: Add unitCode attribute using UN/ECE Rec 20.
Quantity elements must have unitCode attribute.
Engine Classification
Requires user confirmation before application
What is UBL-SR-08?
UBL-SR-08 is a fatal validation rule defined in the ubl-2.1 specification. It validates the InvoicePeriod element in the UBL invoice XML.
When this rule fires, the invoice is rejected by Peppol access points and never reaches the buyer.
Target path: /Invoice/cac:InvoicePeriod
Why This Error Matters
Invoice will be rejected by EN16931 validators. These structural constraints ensure consistent processing by receiving systems.
UBL-SR-08 is a hard failure — the invoice must be corrected and re-sent before it can reach the recipient.
Validator Behavior
- ·Causes invoice rejection
- ·Fails UBL schema validation
- ·Error returned: UBL-SR-08
- ·Specification: ubl-2.1
How to Fix It
Find quantities
InvoicedQuantity, BaseQuantity, etc.
Add unitCode
C62 (unit), HUR (hour), KGM (kg), etc.
XML Example
Generic example based on the rule's target XPath. Your actual XML structure may differ.
<!-- Required block is missing --> <!-- <cac:InvoicePeriod> ... </cac:InvoicePeriod> -->
<!-- Add the required block --> <cac:InvoicePeriod> <!-- child elements --> </cac:InvoicePeriod>
Technical Reference
/Invoice/cac:InvoicePeriodCommon Causes
- ·ERP system exports multiple references where only one is allowed in EN16931
- ·Data consolidation merged records that should have been deduplicated
- ·Template or mapping incorrectly configured to output duplicate elements
- ·Manual editing introduced extra elements
- ·Invoice conversion from another format did not merge duplicate entries
Seeing this in production? The API handles UBL-SR-08 automatically. See the fix response →
Frequently Asked Questions
Quantity elements must have unitCode attribute.
Add unitCode attribute using UN/ECE Rec 20. Invoice Navigator can propose a fix for this error, which you review and confirm before it is applied.
Yes, UBL-SR-08 is a critical error that will cause invoice rejection. It must be fixed before submission.
Related Errors
Related Content
Last updated: 3 March 2026
Validate your invoice
Drop your XML here to check for UBL-SR-08
Fix UBL-SR-08 with one click
Upload your invoice and we'll suggest a fix for your review before applying it.