errorEN 16931

BR-29:Invoice period end date before start date

The Invoicing Period End Date (BT-74) is before the Start Date (BT-73). The end date must be on or after the start date.

Severity
Fatal
Rule set
EN 16931
Country
All EU
Fix type
AUTO-FIX

Engine Classification

Auto-fix: Swap the start and end dates if they are reversed. This is a common data entry error where the dates are correct but in wrong fields.

What is BR-29?

BR-29 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:InvoicePeriod

Why This Error Matters

Invoice rejected. An invalid billing period cannot be processed.

BR-29 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-29
  • ·Specification: EN 16931

How to Fix It

1.

Identify the dates

Find StartDate and EndDate in the InvoicePeriod element

2.

Compare values

Check if EndDate is before StartDate

3.

Swap if reversed

Exchange the date values so StartDate <= EndDate

Before / After

Failing XML
<Invoice>
  <!-- Issue: If both Invoicing period start date and end date are given t -->
</Invoice>
Corrected XML
<Invoice>
  <!-- Issue resolved per EN 16931 -->
</Invoice>

Technical Reference

XPath//cac:InvoicePeriod
SpecEN 16931
Operationswap_dates
StrategyAuto-fix: Swap the start and end dates if they are reversed. This is a common data entry error where the dates are correct but in wrong fields.

Code Example

<cac:PartyTaxScheme>
  <cbc:CompanyID>NL123456789B01</cbc:CompanyID>
  <cac:TaxScheme>
    <cbc:ID>VAT</cbc:ID>
  </cac:TaxScheme>
</cac:PartyTaxScheme>

Common Causes

  • ·Invoice period dates entered in wrong order
  • ·End date before start date due to data entry error
  • ·Date picker UI allowed illogical date range
  • ·Copy-paste from previous invoice with wrong dates
  • ·System timezone issue causing date comparison failure

Seeing this in production? The API handles BR-29 automatically. See the fix response →

Commonly Seen In

All invoicing software

Frequently Asked Questions

The seller must have a VAT identifier or tax registration number.

Add seller VAT number in PartyTaxScheme. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.

Yes, BR-29 is a critical error that will cause invoice rejection. It must be fixed before submission to ensure your invoice is accepted by the recipient's system.

Many instances of BR-29 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues, including seller vat identifier or tax number required.

BR-29 is commonly seen in exports from All invoicing software. These software packages sometimes generate invoices that need adjustment to meet full compliance standards.

See Also

Related Errors

Last updated: 27 February 2026

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Handle BR-29 Automatically in Your Pipeline

The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.