W System / Germany's BMF letter of 15 October 2026 on e-invoicing

Germany's BMF letter of 15 October 2026 on e-invoicing: what changes for invoicing software

In short: the German Federal Ministry of Finance (BMF) published a third letter on mandatory B2B e-invoicing on 15 October 2026. It does not move any deadline and does not introduce a new format or XRechnung version. It settles practical questions that invoicing software has to handle: down payments on final invoices (BT-113 and BT-22 accepted until 30 June 2030), service descriptions, construction invoices, discounts, gross-price invoices, corrections, business-rule errors and penalties. Below: what each section says, with its paragraph number (Rn.), and what it means for your product, plus a checklist and a working example.

The letter in one paragraph

BMF letter of 15 October 2026, reference III C 5 - S 7287-a/00019/021/017, coordinated with the federal states, supplements the letters of 15 October 2024 and 15 October 2025 and amends the VAT application decree (UStAE). Its principles apply to supplies made after 31 December 2024, with the transition rules up to 31 December 2027 still in place. For e-invoices issued until 31 December 2026, the tax office will not object, also for input VAT deduction, if an invoice meets the 2024 and 2025 letters but not the new additional requirements. Source: BMF letter (PDF, bundesfinanzministerium.de).

Deadlines: unchanged

Since 1 January 2025 every business must be able to receive e-invoices for domestic B2B supplies.
From 1 January 2027, issuers with more than EUR 800,000 total turnover in the previous year must issue e-invoices (with the statutory exceptions).
Until 31 December 2027, issuers at or below EUR 800,000 can still use the transition rule, and certain EDI procedures can continue with the recipient's consent. From 2028 the general transition rules end.
New in this letter: some reliefs run to 30 June 2030 (final-invoice deductions, fee notices from public bodies); the gross-price relief ends with invoices issued by 31 December 2027.

What each section says, and what it means for your software

Rn.	What the letter says	What to do in invoicing software
2	Down-payment invoices Down-payment, advance and interim invoices issued before your own e-invoicing obligation starts do not have to be e-invoices, even if the work and the payment come later.	No re-issue job needed for old down-payment invoices when a customer's obligation starts.
3–4	Final invoices Until 30 June 2030 a final invoice may deduct the payments already received as one sum in BT-113 (Paid amount), with the details of the partial payments in BT-22 (Invoice note). Alternatively the deduction can sit in an embedded, unstructured attachment that the structured part points to; that option, previously limited to 31 December 2027, now also runs to 30 June 2030.	Support BT-113 plus a generated BT-22 note listing each down payment (number, date, net, VAT, paid).
5–7	B2B or B2C in mass business Not issuing an e-invoice is not objected to while the issuer did not know, and could not have known with a merchant's diligence, that the customer is a business. For recurring mass contracts with mixed customers (for example energy supply) it is enough to clarify this when the contract starts or changes.	Store the business-customer flag at contract level; no periodic re-checks needed.
8–9	Where the mandatory VAT fields go The VAT-mandatory information of §§ 14, 14a UStG also applies to e-invoices. The tax administration recommends the KoSIT / FeRD mapping table (current version) that assigns each mandatory item to an EN 16931 business term (BT) or group (BG).	Map your invoice fields against the KoSIT / FeRD table and test the result.
10–12	Description of the service The structured part must identify the service clearly enough for the invoice's control function: type, scope, content and, where relevant, place of the service. Extra detail that is not needed for that (for example timesheet breakdowns) can go into an embedded attachment.	Keep line descriptions meaningful in the XML; put long annexes into embedded attachments.
13–14	Construction work Because the core data model cannot carry a bill of quantities (Leistungsverzeichnis), it is currently accepted that the structured part lists only the trades with their sums, if a human-readable embedded attachment breaks them down along the bill of quantities and the structured part clearly refers to it. A GAEB file can be added; the parties can also agree on an extension.	Offer trade-level lines plus an embedded PDF annex and an explicit reference to it.
15–16	Discounts, bonuses, cash discounts Agreed reductions whose amount is not known when invoicing must be referred to clearly; a general reference to a written agreement is accepted if the documents can be produced quickly. A later change to the agreement does not require correcting the invoice.	Let users add a general reference text for bonus or discount agreements.
17–19	Gross-price invoices EN 16931 calculates from net amounts, which can cause rounding differences for gross-priced goods (for example fixed-price books). XRechnung and ZUGFeRD have no gross-price format yet, so for gross-based e-invoices issued until 31 December 2027 the structured part may carry only the totals per VAT rate or exemption, with the full line items in a human-readable embedded attachment that the structured part refers to.	If you price gross, implement the totals-plus-attachment fallback and plan for its end in 2027.
20–21	Corrections A correction must itself be an e-invoice, using an invoice type for corrections, where the e-invoice obligation applies. Which type to use for replacing, cumulative corrections or commercial credit notes is not fixed technically yet; any workable method is fine as long as the original and the corrections together show the final figures clearly.	Make sure corrections are emitted as e-invoices (credit note or corrective invoice type), never as PDFs.
22–23	Business-rule errors The letter separates the tax view from the technical view. Technically, breaking a business rule of the core data model means the file is not an EN 16931 invoice. For VAT purposes, a file with a business-rule error but no format error is still, in principle, an e-invoice; it becomes a content error only if a VAT-mandatory item is affected.	Report schema errors and business-rule errors separately, and flag which ones touch VAT-mandatory fields.
24–25	Public-sector buyers Invoices to public bodies fall under the VAT e-invoice rules only when the body acts as a business, but suppliers are also bound by public e-invoicing rules (for example the federal ERechV since 27 November 2020). Both apply side by side; where they differ, follow the stricter one.	Keep Leitweg-ID (buyer reference) handling and XRechnung output for public buyers.
26–27	Fee notices from public bodies Notices about public-law charges that also count as VAT invoices may, until 30 June 2030, be issued and sent as other invoices instead of e-invoices.	Mostly relevant for public-sector and utility software.
28	Penalties Issuing another kind of invoice where an e-invoice is required is not an administrative offence under § 26a(2) no. 1 UStG.	No fine for that specific breach, but the invoice is still not compliant, so customers will still ask for e-invoices.

Paraphrased from the letter; read the original for the exact wording. Rn. = paragraph number in section I of the letter.

Checklist for invoicing and ERP builders before 1 January 2027

Map every VAT-mandatory item to its BT / BG field using the KoSIT / FeRD table (xeinkauf.de, ferd-net.de).
Final invoices: write the sum of received payments to BT-113 and generate a BT-22 note that lists each down payment.
Always send the delivery or service date (BT-72 or an invoicing period). It is a VAT-mandatory item, and the XRechnung rules warn when it is missing.
Corrections and credit notes go out as e-invoices with a correction or credit-note type, never as PDFs.
Support embedded attachments for timesheets, bills of quantities and gross-price line items, and reference them from the structured part.
Validate every outgoing file against EN 16931 and, for German public buyers, XRechnung; show schema errors and business-rule errors separately.
Store the B2B / B2C classification per contract for mass business.

Example: a final invoice with BT-113 and BT-22

W System, which publishes this page, runs an e-invoice API that creates and validates EN 16931 and XRechnung invoices. The request below creates an XRechnung final invoice of EUR 11,900.00 (incl. 19 % VAT) that deducts one paid down payment of EUR 5,950.00 as prepaid_amount (written to BT-113 Paid amount) and lists the details in note (BT-22). The output is checked against the official CEN EN 16931 and KoSIT XRechnung rules before it is returned. It is a technical example, not tax advice.

curl -X POST https://api.wsystem.dev/einvoice/create \
  -H 'Content-Type: application/json' --data @final-invoice.json

final-invoice.json:

{
 "format": "xrechnung",
 "invoice_number": "SR-2026-031",
 "issue_date": "2026-10-19",
 "due_date": "2026-11-18",
 "currency": "EUR",
 "buyer_reference": "04011000-12345-34",
 "seller": {
  "name": "Muster GmbH",
  "vat_id": "DE123456789",
  "street": "Hauptstr. 1",
  "city": "Berlin",
  "postal_code": "10115",
  "country": "DE",
  "email": "[email protected]",
  "phone": "+49 30 1234",
  "contact_name": "Anna Muster"
 },
 "buyer": {
  "name": "Kunde AG",
  "vat_id": "DE811193231",
  "street": "Ring 2",
  "city": "Muenchen",
  "postal_code": "80331",
  "country": "DE",
  "email": "[email protected]"
 },
 "lines": [
  {
   "description": "Shop relaunch project (final invoice, all milestones)",
   "quantity": 1,
   "unit_price": 10000,
   "vat_rate": 19
  }
 ],
 "payment": {
  "iban": "DE89370400440532013000",
  "terms": "30 days net"
 },
 "prepaid_amount": 5950,
 "note": "Schlussrechnung. Abgesetzte Abschlagszahlung: Abschlagsrechnung AR-2026-014 vom 15.09.2026, Entgelt 5.000,00 EUR, USt 19 % 950,00 EUR, gezahlt 5.950,00 EUR am 25.09.2026.",
 "delivery_date": "2026-10-16"
}

Real response from the live API on 19 October 2026 (the generated XML left out):

{
 "valid": true,
 "format": "xrechnung",
 "syntax": "UBL 2.1",
 "totals": {
  "currency": "EUR",
  "line_total": "10000.00",
  "vat_total": "1900.00",
  "total_with_vat": "11900.00",
  "payable": "5950.00"
 },
 "errors": [],
 "warnings": [],
 "checked": {
  "xsd": true,
  "EN16931": true,
  "XRechnung": true,
  "PeppolBIS3": false
 }
}

Without delivery_date the same request still validates but returns the XRechnung warning BR-DE-TMP-32 (no delivery date, invoicing period or line period), which is exactly the kind of gap worth fixing before 2027. You can check existing files with POST /einvoice/validate; every error comes with its rule ID and the business terms involved, so you can see whether a VAT-mandatory field is affected. Free for 20 calls a day per IP without a key; details on the e-invoice validation API page.

Questions and answers

Does the BMF letter of 15 October 2026 postpone the German e-invoicing obligation?

No. It adds clarifications and some transition rules but keeps the statutory timeline: e-invoices have to be received since 1 January 2025, issuers with more than EUR 800,000 prior-year turnover must issue them from 1 January 2027, and the remaining transition rules end on 31 December 2027.

What is the reference of the letter?

BMF letter of 15 October 2026, III C 5 - S 7287-a/00019/021/017, a coordinated decree with the federal states. It supplements the BMF letters of 15 October 2024 (BStBl I p. 1320) and 15 October 2025 (BStBl I p. 1806) and amends the VAT application decree (UStAE).

Do e-invoices issued in 2026 have to follow the new letter?

Not strictly. For e-invoices issued until 31 December 2026, the tax office will not object, also for input VAT deduction, if they meet the 2024 and 2025 letters but not the additional requirements of the new letter.

How do I show down payments on a final e-invoice?

Until 30 June 2030 you can put the total of the payments already received in BT-113 (Paid amount) and list the details of each partial payment in BT-22 (Invoice note), or put the deduction into an embedded attachment that the structured part refers to.

Is an invoice with a business-rule error still an e-invoice?

For VAT purposes it can be: the letter says a file with a business-rule error but no format error is in principle still an e-invoice under section 14 UStG, and it is only a content error if a VAT-mandatory item is affected. Technically it is not an EN 16931 invoice, so receiving systems may still reject it.

Is there a fine for sending a PDF instead of an e-invoice?

The letter says that issuing another kind of invoice instead of a required e-invoice is not an administrative offence under section 26a(2) no. 1 UStG. It does not make the PDF compliant.

Sources

Article checked against the BMF original on 19 October 2026.

Facts checked 2026-10-19. W System is the maker of this product. Not affiliated with the European Commission. Not legal or tax advice.