Letter from the Federal Ministry of Finance dated October 15, 2025, regarding eInvoicing: Key changes at a glance

However, over the past few months, it has become clear that the implementation has raised many detailed questions—particularly regarding the classification of error types, technical validation, and the retention of eInvoices.

Small and medium-sized enterprises and IT service providers, in particular, repeatedly pointed out that individual points in the BMF letter could be interpreted in different ways. For example, it remained unclear when an invoice is actually considered “proper,” how to handle minor deviations in data structure, or whether an eInvoice still meets the requirements if it is archived outside of a GoBD-compliant system.

The Federal Ministry of Finance responded—and published an initial draft of a clarification letter as early as the summer of 2025 to resolve these ambiguities. However, the final version dated October 15, 2025 now goes significantly beyond this draft. It contains not only editorial adjustments but also new definitions and substantive additions, for example regarding error classification, validation procedures, regulations for small businesses, and correction obligations.

Thus, the new letter is not merely an update, but a genuine clarification of key issues regarding eInvoice implementation in Germany. It demonstrates that eInvoice has become established in practice—and that the legislature has responded to feedback from the business community.

We have examined the most important changes in detail and summarize them below in a clear and understandable manner:

1. New Definitions: What the BMF now considers “errors”

One of the most important changes concerns the introduction of new terms. For the first time, the BMF clearly distinguishes between three types of errors:

• Format errors: The file does not conform to the prescribed structured format (e.g., XRechnung, ZUGFeRD-compliant XML). Such an invoice is not considered an eInvoice, but only an “other invoice.”
• Business rule errors: The file is technically correct but violates the logical structure of the eInvoice—for example, if mandatory fields are missing or the totals do not add up.
• Content errors: Legally required information (§ 14, § 14a UStG) is incorrect or incomplete.

This makes it clear: Not every error has the same consequences. Furthermore, the BMF explicitly emphasizes that while technical validation can help detect such errors early on, it does not replace a content review.

2. Small businesses, small-amount invoices, and travel tickets: Who is allowed to do what according to the BMF letter?

The exceptions to mandatory eInvoicing have also been tightened. Small businesses may continue to send invoices in other electronic formats, but they require the receiver’s consent to do so. eInvoices as defined by the EN 16931 standard, however, may be transmitted without consent. The previous regulations regarding small-amount invoices and travel tickets have been expanded and standardized—they are now explicitly considered part of the same exception group.

3. Corrections and Discounts: When Is a New eInvoice Required?

The letter now clearly distinguishes between pure price changes and changes in content:

• If only the price or the basis of assessment changes (for example, due to discounts or price reductions), no new eInvoice is required according to the BMF letter.
• However, if the service content changes—such as the quantity or type of service—a new, corrected invoice with a clear reference to the original invoice must be issued.

This clarification finally provides legal certainty on an issue that has often been interpreted differently in the past.

4. Technical Clarifications from the BMF Letter 2025: Mandatory Information, Data Structure, and Validation

The BMF reaffirms: All mandatory information must be included in the structured part of the eInvoice—that is, in the XML file itself. A reference to attachments or external documents is not sufficient. This means: Only what is contained in the machine-readable part is legally considered part of the invoice content. All German companies that already send electronic invoices (or will be legally required to do so by 2027 at the latest) should therefore ensure that their systems correctly populate all relevant BT fields (Business Terms). If, for example, the BT-10 (Buyer reference) field is missing, the invoice may be considered incomplete despite having the correct format.

5. Retention: Less Bureaucracy, More Flexibility

A welcome change, however, concerns the archiving requirements. The structured part of the eInvoice must be retained for eight years (Section 14b UStG). What is new, however, is that storage may also take place outside a GoBD-compliant system, as long as the data remains unchanged and traceable.

In doing so, the BMF is adopting a more practical approach—especially for smaller businesses that previously feared the high requirements for electronic archiving systems.

6. Transition provisions: What applies and until when

The existing transition provisions remain in effect:

• Since the introduction of mandatory eInvoicing on January 1, 2025: Obligation as a receiver to receive electronic invoices.
• Starting January 1, 2027: Obligation to issue electronic invoices for all companies with an annual turnover exceeding 800,000 euros.
• Until the end of 2027: Transition provisions for small businesses and existing EDI systems.

The BMF thus confirms that while companies have time to make the transition, they should use it wisely.

What does the BMF letter achieve? An important step toward greater clarity!

The new BMF letter is not a new legislative change, but an important step for practical implementation. It provides clarity where uncertainty previously existed—regarding error definitions, validation, archiving, and transition periods. Companies that have previously relied on PDF invoices or simple email transmissions should take this opportunity to transition their processes now to eInvoice in accordance with EN 16931. With standardized formats such as XRechnung or ZUGFeRD, companies can not only meet legal requirements but also automate processes and minimize sources of error.