BR-29 — E-Invoice Validation Rule & Fix

Fixture ID: invertedPeriod · XPath: /ubl:Invoice/cac:InvoicePeriod/cbc:EndDate

1. Why This Rule Triggers (Diagnostic Message)

The invoicing period runs from "2026-07-31" (BT-73) to "2026-07-01" (BT-74), which ends before it starts. EN 16931 requires the end date to be later than or equal to the start date; equal is allowed, because a single-day period is a real thing. An inverted period is almost always two fields transposed, and it is worth catching here rather than downstream: a consumer that computes a duration from it gets a negative number and either books the accrual to the wrong period or divides by it.

2. How to Fix BR-29

Swap invoicingPeriod.startDate and invoicingPeriod.endDate, or correct whichever of the two is wrong. Use the same date in both fields for a period of one day.

3. Valid Code / Payload Example

"invoicingPeriod": { "startDate": "2026-07-01", "endDate": "2026-07-31" }