Peppol BIS 4.0: the PINT and UBL merger explained
Peppol BIS 4.0 is the new, globally intended invoicing format through which OpenPeppol is closing the gap between UBL BIS Billing 3.0, the European standard format, and PINT, the international variant used outside Europe. For IT decision makers, Peppol service providers, and finance teams looking to future-proof their invoicing systems, this is a development worth tracking now, even though an exact release date has not yet been confirmed.
Why this matters
Peppol currently runs two parallel format families. UBL BIS Billing 3.0 is widely used across Europe, including for the Belgian and Dutch e-invoicing mandates. PINT (Peppol International) is the generic international variant, with local extensions per country, such as PINT-OM for Oman or PINT-AE for the United Arab Emirates. This two-track approach was necessary to roll out Peppol quickly outside Europe without breaking the European standard, but in practice it adds complexity for service providers and software vendors operating internationally: two sets of validation rules, two documentation tracks, and two upgrade paths to maintain.
With Peppol BIS 4.0, OpenPeppol combines both tracks into a single base format, on top of which country-specific extensions are applied as add-ons rather than as fully separate specifications. This is not just a technical clean-up: it makes cross-border interoperability simpler, since an invoice that meets the BIS 4.0 core standard should in principle be processable in any Peppol country, with only the country-specific fields as variables.
What actually changes
OpenPeppol positions Peppol BIS 4.0 as a consolidated base model combining the strengths of both UBL BIS 3.0 and PINT. Concretely, this means a shared core set of mandatory and optional fields, a unified validation layer, and an architecture where country-specific requirements (such as additional tax fields or extra identification codes) become separate extension modules on top of the core standard, rather than fully standalone specifications as is currently the case with PINT variants.
For businesses already using UBL BIS Billing 3.0, this is not expected to be a radical break: the existing European core fields should remain largely recognisable. For service providers serving both European and international clients, the main benefit is that a single validation and processing engine will eventually cover both worlds, instead of maintaining two separate implementations.
Denmark as an early test case
One concrete signal that the market is taking this seriously comes from Denmark. The Danish Business Authority published a strategy paper in March 2026 announcing that the country will fully phase out its national format, OIOUBL, and migrate to a localised version of Peppol BIS 4.0, branded NemHandel BIS 4. Denmark made this choice explicitly after negative market feedback on a planned OIOUBL 3.0 upgrade, opting for a single internationally interoperable standard instead of the dual-format architecture it had maintained for nearly two decades.
Denmark’s timeline illustrates how carefully such a transition is being approached: development of NemHandel BIS 4 and the Danish extensions in 2027, a release candidate and final release in 2028, and a full transition to NemHandel BIS 4 by mid-2029, with OIOUBL 2.1 phased out. For businesses trading with Danish partners, this gives a concrete sense of the pace at which BIS 4.0 is being rolled out in practice: not overnight, but with a clearly announced direction.
Timeline and open questions
OpenPeppol has not yet published a definitive release date for Peppol BIS 4.0. Various sources point to an expected launch sometime in 2026, followed by a longer transition period during which BIS 3.0, PINT, and BIS 4.0 coexist. In practice, this means no urgent action is required yet, but it is worth tracking the development, especially for organisations that build or maintain invoicing software themselves rather than fully outsourcing this to a Peppol service provider. A transition period in which multiple formats remain valid side by side is not new for Peppol: the earlier introduction of UBL BIS Billing 3.0 also had a generous overlap period with its predecessor format, giving service providers and software vendors enough time to migrate without interrupting service.
The relationship with ViDA and national mandates
Peppol BIS 4.0 does not exist in isolation from the broader European ViDA (VAT in the Digital Age) development. From 2030, ViDA mandates digital reporting of cross-border B2B transactions within the EU, and the underlying semantic standard EN 16931 forms its basis, the same standard on which today’s Peppol BIS formats are already built. A consolidated, global format like BIS 4.0 fits logically into this picture: the fewer format variants circulating worldwide, the easier it becomes to meet both national mandates and future EU-wide reporting obligations from a single technical foundation. For countries currently revisiting their national format, such as Denmark with NemHandel, the choice for BIS 4.0 is partly driven by a desire to avoid migrating twice, first to an interim national format and then again to the eventual global Peppol standard.
What it means for software vendors and developers
For organisations building their own invoicing or accounting software, the merger carries concrete technical consequences. Validation rules currently maintained separately for UBL BIS 3.0 and for PINT will eventually need to converge into a single rule set with country-configurable extensions. That is an investment in restructuring, but it pays off over the long term through lower maintenance overhead: bug fixes and updates to the core validation logic only need to be applied in one place instead of across two parallel codebases. Developers building a new Peppol integration today would do well to prepare their architecture for a separated core-and-extension layer where possible, even though BIS 4.0 is not yet available. That prevents today’s investment from largely having to be redone once the eventual transition arrives.
A practical checklist for IT teams and service providers
Organisations wanting to get ahead of Peppol BIS 4.0 should focus on the following:
- Follow OpenPeppol’s documentation and the Peppol BIS Billing specification for concrete release announcements, rather than relying on secondary sources or rumours.
- Ask your Peppol service provider whether and when a migration path to BIS 4.0 is planned, especially if invoicing is partly managed in-house.
- When expanding internationally, keep in mind that new country implementations, such as Oman or the United Arab Emirates, currently still run on PINT variants, and that the move to BIS 4.0 will follow its own timeline per country.
- Use Denmark’s approach as a benchmark for a realistic pace: an announcement in 2026, technical development in the following years, and a full transition only several years later.
- Make sure validation and invoice-processing systems are built modularly enough to absorb a future format extension without a full rebuild.
- Ask your ERP or accounting software vendor whether BIS 4.0 is already on their product roadmap, especially if invoicing for multiple countries runs through a single system.
- Document which country-specific extensions are currently in use (for example for French, Belgian, or international customers), so that at the time of eventual migration it is immediately clear which extension modules still need to be supported.
What this means for choosing a service provider
For businesses still selecting a Peppol service provider, or reconsidering their current one, the upcoming merger is an extra criterion worth weighing: a provider that is internationally active and has concrete experience with both UBL BIS 3.0 and PINT implementations is generally better positioned to handle a future move to BIS 4.0 smoothly than a provider operating only within the European market. Compare service providers on experience, supported formats, and international coverage via the Peppol.nu comparison tool, and read more background on how Peppol invoices are technically structured in the complete guide to Peppol invoices.
Peppol BIS 4.0 is not yet an urgent action item, but it is a development that will shape how simple cross-border e-invoicing becomes over the next few years. Organisations already working with an internationally oriented service provider and building their systems modularly will be best positioned when the eventual transition arrives.
