# BR-DE-26 Corrected invoices should reference the preceding invoice

When invoice type code BT-3 is 384 for a corrected invoice, XRechnung expects at least one preceding invoice reference (BG-3).

## Problem Description

When invoice type code BT-3 is 384 for a corrected invoice, XRechnung expects at least one preceding invoice reference (BG-3).

> **WARNING**: XRechnung 3.0

## Context and Significance

This rule is warning-level in the pinned XRechnung bundle, but recipients often need the original invoice reference for matching and audit trails.

## Solution

Add the original invoice number and issue date in BG-3 before exporting the corrected invoice.

- validate
- convert

## Valid Examples

- BT-3 = 384 and BG-3 references INV-2026-001

## Invalid Examples

- Corrected invoice without BG-3

## Technical Details

### Affected Fields
BT-3 Invoice type code, BG-3 Preceding invoice reference

## Validation Tools

- [Official KoSIT Validator](https://erechnungsvalidator.service-bw.de/): Validate your XRechnung files against all BR-DE rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Automatic validation error fixes when converting.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [Complete Error List](/resources/kosit-validator-errors): Overview of all German XRechnung validation rules.