Denmark Confirms Transition to a Single Peppol-Based E-Invoice Specification by Mid-2029

On May 27, 2026, the Danish Business Authority (Erhvervsstyrelsen) published the results of its public consultation on the future document strategy for the NemHandel e-invoicing infrastructure.

Following 12 consultation responses, the authority confirmed that the transition from the national OIOUBL format to a single, common e-invoice specification based on Peppol BIS will proceed, starting with the invoice document.

Implementation now moves forward under the project “Én fælles e-faktura specifikation” (One Common E-Invoice Specification), which held its kick-off with public and private stakeholders on June 4, 2026.

Background

Denmark is one of Europe’s e-invoicing pioneers: business-to-government e-invoicing has been mandatory since 2005, and the national NemHandel infrastructure today runs in parallel with the Peppol network. Under the Danish Bookkeeping Act, businesses have been phased into mandatory digital bookkeeping, and digital accounting systems must support sending and receiving e-invoices and exporting data in a standard (SAF-T-based) format.

Danish businesses have been phased into these digital-bookkeeping requirements between 2024 and 2026. Importantly, this is a capability requirement—accounting systems must be able to send and receive structured e-invoices—and not a general B2B e-invoicing mandate: Denmark does not oblige businesses to exchange e-invoices for domestic B2B transactions.

Denmark currently operates two document standards side by side: the national OIOUBL format and Peppol BIS. Both are based on the UBL 2.1 syntax and conform to the European e-invoicing standard EN 16931. In March 2026, Erhvervsstyrelsen consulted publicly on a new document strategy to end this duality.

The consultation ran from March 11 to March 27, 2026, and drew 12 responses; the consultation memorandum (høringsnotat) summarizing the feedback was finalized on May 18, 2026, and published on May 27, 2026.

The Change

The consultation outcome confirms the strategic decision: Denmark will harmonize on one common e-invoice specification based on Peppol BIS (the forthcoming NemHandel BIS profile built on Peppol BIS 4 with limited Danish national extensions), and the OIOUBL format will be phased out.

As of mid-2026, however, the currently released OpenPeppol specification remains Peppol BIS Billing 3.0; the referenced Peppol BIS 4 is a forthcoming next-generation profile still under development, not a released standard that businesses can implement today. Key themes from the consultation responses include:

• Broad stakeholder support for harmonization toward a single Peppol-based format, with international compatibility highlighted so the solution satisfies both Danish needs and upcoming EU regulation.
• Concerns about complexity and cost if Danish national extensions become too numerous or extensive.
• Requests to preserve functionality available in OIOUBL 2.1 for industries and end users with special requirements.
• Feedback that a six-month migration window would be too short, and requests for a more detailed transition plan.

Erhvervsstyrelsen states that it will balance simplicity against concrete business needs, and a long phase-in period against timely completion well before the EU ViDA requirement for structured cross-border e-invoicing takes effect on July 1, 2030. The balance is to be found through structured cooperation with public and private stakeholders within the implementation project.

Scope

The transition affects every business, public authority, ERP vendor, and service provider that issues or receives e-invoices through NemHandel or Peppol in Denmark. The harmonization starts with the invoice document; related document types are expected to follow. Danish subsidiaries of multinational groups that currently generate OIOUBL invoices from their ERP systems will ultimately need to move to the new Peppol BIS 4-based specification.

Timeline

• March 11–27, 2026 – Public consultation on the document strategy (12 responses received).
• May 27, 2026 – Consultation memorandum published; transition from OIOUBL to Peppol confirmed, starting with the invoice.
• June 4, 2026 – Kick-off of the implementation project “Én fælles e-faktura specifikation.”
• 2026–2027 – Finalization of the technical basis (Peppol BIS 4 with Danish extensions).
• 2028 – Release candidate and final version of the new specification expected.
• 2028 to mid-2029 – Gradual migration of businesses and service providers; full migration targeted for mid-2029, after which OIOUBL is phased out.
• July 1, 2030 – EU ViDA digital reporting and e-invoicing requirements for intra-EU transactions take effect.

Businesses Affected

All Danish VAT-registered businesses using digital accounting systems, ERP vendors, and bookkeeping software providers serving the Danish market, Peppol access points and NemHandel service providers, and foreign groups with Danish entities that invoice via OIOUBL today. Businesses already invoicing in Peppol BIS format will face a comparatively smaller uplift to the BIS 4-based specification.

Required Actions

• Inventory where OIOUBL is generated, received, or archived in your systems landscape, including middleware and OCR/AP automation flows.
• Engage your ERP vendor or service provider on their roadmap toward Peppol BIS 4 and the Danish NemHandel BIS profile.
• Follow the working groups under the “One Common E-Invoice Specification” project to anticipate the treatment of Danish national extensions.
• Plan the migration alongside other Danish digital obligations, including SAF-T-based data export requirements under the Bookkeeping Act.
• For multinational groups: align the Danish migration with broader EU ViDA readiness, since Peppol BIS 4 is designed to converge with the EN 16931-based EU framework.

Practical Implications

For most businesses the change is evolutionary rather than disruptive: exchange infrastructure remains NemHandel/Peppol, and the reform reduces long-term complexity by eliminating dual-format maintenance. The main risks sit with ERP templates, custom validations, and industry-specific fields that rely on OIOUBL 2.1 functionality. The consultation feedback on the short phase-in window suggests the final migration plan will be a critical parameter to monitor — businesses should not assume a lengthy parallel-running period.

Expected Next Steps

Erhvervsstyrelsen will define and execute the cooperation process under the implementation project, publish the technical basis for the new specification during 2026–2027, and communicate the detailed migration plan. A release candidate is expected in 2028, with migration completed by mid-2029 — deliberately ahead of the ViDA cross-border e-invoicing requirement of July 1, 2030.

How Can KGT Support You?

KGT specializes in SAP-integrated e-invoicing solutions and add-ons for e-invoicing and digital reporting mandates across Europe. KGT supports SAP Document and Reporting Compliance (SAP DRC) implementations and builds certified SAP add-ons where native coverage is missing, including Peppol-based scenarios. If your organization needs to prepare its SAP landscape for Denmark’s transition to Peppol BIS 4 or for ViDA more broadly, we are happy to arrange a demonstration and answer your questions.

Official sources

• NemHandel / Erhvervsstyrelsen – Consultation on the transition to Peppol concluded (May 27, 2026) – View source
• Erhvervsstyrelsen – Consultation memorandum (høringsnotat), document strategy (PDF) – View source
• Erhvervsstyrelsen – Nemhandel: common digital infrastructure – View source

This publication is provided for general information purposes only and does not constitute tax, legal, or other professional advice.