The Hague, 26 June 2026 – The Dutch Peppol Authority (NPa) has published the May 2026 release of updated validation rules for Peppol BIS 3 and SI-UBL 2. This Peppol BIS 3 validation update August 2026 becomes mandatory on 17 August 2026 — less than eight weeks from now. Peppol Service Providers, ERP vendors and middleware suppliers that do not implement the update in time risk having their invoices rejected on the Peppol network.
What Has Changed?
The May release contains updated validation artefacts for two Dutch Peppol standards. For Peppol BIS Billing 3.0, the underlying EN 16931 validation rules have been updated to version 1.3.16. For SI-UBL 2 — the NLCIUS implementation used for Dutch invoices — the schematrons, XSD files and supporting validation files have also been revised.
The NPa follows a standard bi-annual release cycle: a spring and an autumn release, with new rules becoming mandatory after a three-month transition period. That transition period ends on 17 August 2026.
Although the changes are technical in nature, the operational impact is direct: validation artefacts determine whether an invoice is accepted or rejected by receiving systems on the Peppol network. An invoice that does not comply with the updated rules will be automatically refused after 17 August 2026.
Which Systems Need to Be Updated?
The update is relevant to anyone generating, validating or routing invoices via the Dutch Peppol network.
Peppol Service Providers operating as certified access points on the Peppol network are responsible for updating their validation environments in time. They must implement the new artefacts in both their production and test environments before 17 August 2026.
ERP vendors and middleware suppliers that have integrated Peppol validation into their own software must incorporate the new version of the schematrons and XSD files in their next release. Updated artefacts are available via the official NPa GitHub repository.
End users who send or receive invoices via a Peppol Service Provider generally do not need to take action themselves. Responsibility for the update lies with their Peppol Service Provider. It is, however, worth verifying that your current provider is implementing the update on time.
What Is EN 16931 and Why Does Version 1.3.16 Matter?
EN 16931 is the European standard that defines the semantic data model for electronic invoices. It forms the basis for both Peppol BIS 3 and national variants such as NLCIUS (SI-UBL 2). Version 1.3.16 contains corrections and clarifications that affect validation logic for specific invoice fields and business rules. Although this is not a fundamental revision, even minor updates to validation rules can cause invoices that were previously accepted to be rejected after the update takes effect.
Practical Steps for Peppol Service Providers
Service providers that have not yet begun implementing the May release should act as soon as possible. The recommended steps are as follows. Download the updated validation artefacts from the NPa website. Implement the new schematrons and XSD files in the test environment and run regression tests on existing invoice flows. Deploy the update to the production environment well before 17 August 2026. Notify clients in advance if the update affects their invoice flows or integrations.
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