Ahead of the next phase of Germany’s B2B e-invoicing mandate, the German Federal Ministry of Finance (Bundesministerium der Finanzen – BMF) published another BMF letter [↗︎] on October 15 2026. This letter provides additional guidance, following previous letters of October 15, 2024 and October 15, 2025. The new guidance aims at clarifying several practical and technical aspects of mandatory electronic invoicing for domestic B2B transactions.
From January 1, 2027, large businesses, whose annual turnover exceeded EUR 800,000 in the previous calendar year will generally be required to issue electronic invoices. These invoice must be compliant with the European Norm (EN) 16931 for domestic B2B transactions in Germany. All other businesses will generally be required to issue e-invoices from January 1, 2028.
Tax-valid invoices with validation rule violations
The guidance establishes distinction between technical validation (including business rules) and tax validity. Business rule errors do not automatically void an e-invoice for tax purposes. A file remains a valid invoice if it contains accurate statutory details.
As a consequence, Service Providers or software vendors must classify validation rules as “tax-relevant” only in case they concern tax-relevant fields. Only if one of these fails, the invoice becomes automatically invalid for tax purposes.
Required content and data mapping
The circular clarifies mandatory invoice content and structural data fields:
- Tax authorities recommend the mapping tables for mandatory tax information from KoSIT [↗︎] and FeRD [↗︎] for EN 16931 alignment.
- Structured data must contain all essential information for tax verification. This includes service type, scope, content, and location.
- Construction services receive dedicated relief due to limits of currently available invoice formats. Sellers can list trade summaries in structured data while embedding full service specifications in attachments.
- Standard discount agreements only require general references if records are easily verifiable.
Corrections, public authorities and fines
Invoice corrections must use structured formats, but flexible correction methods remain acceptable.
Transactions invoiced by public bodies follow tax rules only during commercial activity. Furthermore, public fee assessments can use standard invoice formats until June 2030.
There is currently no fine for issuing an invoice in a format that does not comply with EN 16931, or in a non-electronic format, instead of a required e-invoice. This however does not reduce the adverse effects of non-electronic invoices in tax audits, corrections and input tax deductions.
Transition rules and billing methods
Sellers do not need to issue advance invoices electronically before the end of the transitional period applying to them, even if the supply completes only after the mandate takes effect.
In addition, end invoices may summarise previous partial payments in structured field BT-113 until end of June 2030.
Detail breakdowns can also remain in free-text fields or embedded attachments. The guidance also resolves rounding issues for gross price invoices. In this case, businesses can present summary totals in the structured format until December 2027. They must, however, attach human-readable line items to support the summarised data.
