BR-CO-20:Invoice line period dates required
If Invoice line period (BG-26) is used, the Invoice line period start date (BT-134) or the Invoice line period end date (BT-135) shall be filled, or both.
Engine Classification
Remove empty invoice line period elements that lack both start and end dates
Confidence: 85% · Applied automatically in pipeline
What is BR-CO-20?
BR-CO-20 is a fatal validation rule defined in the EN 16931 specification. It validates the InvoicePeriod element in the UBL invoice XML.
When this rule fires, the invoice is non-compliant and will be rejected by Peppol access points and national validation services. The sending system receives a rejection response and the invoice does not reach the buyer.
Target path: //cac:InvoiceLine/cac:InvoicePeriod[not(cbc:StartDate) and not(cbc:EndDate)]
Why This Error Matters
Invoice rejected. A service period without dates cannot be validated.
BR-CO-20 is a hard failure. Invoices that trigger this rule are rejected at the access point and never reach the recipient. In Peppol networks, this means your sending system receives an MLR (Message Level Response) with a rejection status. The invoice must be corrected and re-sent, adding delay to your payment cycle.
Invoice Navigator can automatically correct this error in your pipeline. The fix is applied with full audit evidence, so your compliance trail remains intact.
Validator Behavior
- ·Causes invoice rejection
- ·Error returned: BR-CO-20
- ·Specification: EN 16931
How to Fix It
Check line period
Look for cac:InvoicePeriod within cac:InvoiceLine that has no dates
Add dates or remove
Either add StartDate (BT-134) and/or EndDate (BT-135), or remove the empty InvoicePeriod element
Verify fix
Ensure the InvoiceLine either has no InvoicePeriod or has at least one date
Before / After
<cac:InvoiceLine> <cac:InvoicePeriod><!-- invalid or missing value --></cac:InvoicePeriod> </cac:InvoiceLine>
<cac:InvoiceLine> <cac:InvoicePeriod>correct-value</cac:InvoicePeriod> </cac:InvoiceLine>
Technical Reference
//cac:InvoiceLine/cac:InvoicePeriod[not(cbc:StartDate) and not(cbc:EndDate)]Common Causes
- ·Line period present but dates are empty
- ·InvoiceLine/InvoicePeriod exists without dates
- ·Line period section added but dates not populated
- ·Template creates empty line period structure
- ·Conditional line period dates not filled
Seeing this in production? The API handles BR-CO-20 automatically. See the fix response →
Frequently Asked Questions
BR-CO-20 occurs when an InvoicePeriod element exists within an InvoiceLine but contains no StartDate (BT-134) or EndDate (BT-135). The period element must have at least one date.
Either add dates to the line period (StartDate and/or EndDate), or remove the empty InvoicePeriod element entirely. Invoice Navigator can fix this automatically by removing empty period elements.
Yes, BR-CO-20 is a business rule violation that will cause invoice rejection. A service period on a line item must have at least one date to be valid.
Yes! Invoice Navigator automatically removes empty InvoicePeriod elements from invoice lines when no dates are present. This is a safe structural fix with no data loss.
See Also
Related Errors
Last updated: 27 February 2026
Handle BR-CO-20 Automatically in Your Pipeline
The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.