XAdES Transition Roadmap 2026-2027: What Businesses Need to Know

In November 2026, the XAdES digital signature standard is scheduled for implementation as part of the Department of Taxation’s plan to upgrade its electronic invoice and electronic document systems. This marks a significant development for businesses using electronic invoices, but it does not mean that all businesses must complete the transition in November. Under the announced roadmap, digital signatures using the existing DSig standard will continue to be accepted through April 9, 2027. This transition period gives businesses time to learn about the new standard, coordinate with their service providers, and prepare any necessary adjustments before adopting it.

Are Businesses Required to Switch to XAdES Immediately in November 2026?

Businesses are not required to complete the transition to XAdES in November 2026. This is the scheduled implementation period for the new digital signature standard under the Department of Taxation’s system upgrade plan, while the existing DSig standard will remain accepted throughout the transition period.

XAdES (XML Advanced Electronic Signatures) is an advanced electronic signature standard built on XML Signature technology. During the transition period, the electronic invoicing system will continue to accept both the existing DSig standard and the new XAdES standard. 

The adoption of XAdES forms part of the Department of Taxation’s plan to upgrade its electronic invoice and electronic document systems, as outlined in Official Letter No. 7714/CT-CĐS dated October 16, 2026. The plan consists of four implementation phases running from September to December 2026, with the adoption of XAdES scheduled for November.

However, the implementation date of the new standard and the deadline for accepting the existing standard are two distinct milestones. Decision No. 1233/QĐ-CT dated August 27, 2026, specifies that the digital signing system will accept both DSig and XAdES during the transition period, with DSig remaining accepted through April 9, 2027.

This means businesses currently using DSig should not assume that their electronic invoicing software must cease operating or be modified immediately in November. Instead, they can use the transition period to confirm whether their existing solutions support XAdES and agree on an appropriate upgrade plan with their service providers.

What Is the XAdES Transition Roadmap for 2026-2027?

The transition roadmap includes several key milestones, reflecting both the system upgrade schedule and the deadlines for accepting existing standards.

November 2026 marks the scheduled introduction of XAdES by the Tax Department. At this stage, businesses should begin confirming with their service providers whether their solutions support the new standard, particularly if their electronic invoicing software is integrated with other systems.

The next key milestone is December 31, 2026, the final date on which data messages using version 2.1.0 will be accepted. During the transition period, the tax administration information system will accept both versions 2.1.0 and 2.1.1. From January 1, 2027, the system will have completed its upgrade and will accept only version 2.1.1.

April 9, 2027, marks the end of the acceptance period for digital signatures using the DSig standard. The digital signature system is scheduled to be upgraded in accordance with the tax authorities’ roadmap, with completion required before April 10, 2027.

Among these milestones, April 9, 2027, is particularly important for businesses still using DSig. Before the transition period ends, businesses should coordinate with their service providers to ensure that their digital signing solutions comply with the standards accepted by the system.

Why Are the Deadlines of December 31, 2026, and April 9, 2027, Different?

These two deadlines relate to different components of electronic invoice processing.

Put simply, when an invoice is generated and submitted to the tax authorities, the software must ensure that the data is structured in accordance with the requirements of the receiving system. This requirement concerns the data message version. By contrast, the digital signature standard defines how signatures are created and verified on electronic data. Therefore, upgrading the data message version from 2.1.0 to 2.1.1 and transitioning the digital signature standard from DSig to XAdES are subject to separate transition deadlines.

However, this does not mean that every combination of data message version and digital signature standard will necessarily be accepted by the system. Businesses should confirm solution compatibility and the appropriate upgrade plan with their service providers.

For businesses using standalone electronic invoicing software, these changes may be handled by the service provider during system updates. For businesses whose electronic invoicing systems are integrated with point-of-sale (POS), accounting, or enterprise resource planning (ERP) software, additional testing may be necessary to ensure that data continues to be transmitted and received correctly.

What Should Businesses Prepare Before the Transition Period Ends?

Transitioning to XAdES does not necessarily require every business to replace its entire electronic invoicing system. The scope of the required changes depends on the software, digital signing method, and operational setup currently in use.

For Businesses Using Electronic Invoicing Software Provided by a Service Provider

If a business currently creates and issues invoices directly through a service provider’s electronic invoicing software, the first step is to confirm whether the existing solution already supports XAdES.

Depending on how the system operates, the service provider may carry out some or all of the necessary upgrades within its own system. In such cases, businesses may not need to replace their existing software.

However, if a business signs invoices using a USB token through a locally installed signing application, the transition may require an update to the signing tool in accordance with the service provider’s instructions.

Therefore, in addition to confirming whether the electronic invoicing software supports XAdES, businesses should also determine whether their current digital signing method requires any adjustments.

For Businesses with Integrated ERP, POS, or Accounting Systems

For businesses operating multiple interconnected software systems, the transition should be assessed across the entire invoice issuance process.

For example, in a retail store, transaction information may first be recorded in the POS system and then transferred to the electronic invoicing software for invoice creation and digital signing. The invoice issuance results are then synchronized back to the management system for recordkeeping or reconciliation.

A change in the digital signature standard does not necessarily require every system involved in this process to be upgraded. However, if a particular system directly processes or verifies digital signature data, additional adjustments or testing may be required.

IT teams should therefore work closely with service providers to identify potentially affected components and test invoice creation, signing, transmission, and receipt before deploying the upgraded system.

For Businesses Implementing a New Electronic Invoicing Solution

Businesses selecting or implementing electronic invoicing software in late 2026 or early 2027 should consider XAdES support as one of the criteria when evaluating potential solutions.

In addition to the digital signature standard, businesses should confirm which data message versions are supported and whether the solution can integrate with the software they currently use.

Clarifying these requirements during the implementation phase can help minimize additional adjustments after the system becomes operational.

Does Switching to XAdES Require Replacing USB Tokens or Re-registering Digital Signatures?

Transitioning from DSig to XAdES does not automatically require businesses to replace their USB tokens or have their digital certificates reissued. XAdES changes the standard and structure of digital signatures applied to XML data, whereas a digital certificate is used to authenticate the signer.

However, businesses may need to update their software or digital signing tools to generate signatures that comply with the new standard. The specific scope of these changes should be confirmed with the relevant solution provider.

Regarding electronic invoicing registration procedures, it is important to distinguish between a change in the digital signature standard and a change in information previously registered with the tax authorities.

However, if the transition also involves changes to digital certificates, service providers, or other registered electronic invoicing information, businesses should review the corresponding update procedures under applicable regulations.

To avoid unnecessary administrative work, businesses should consult their service providers to confirm whether their existing digital certificates and signing methods can continue to be used, as well as whether any additional procedures are required.

How FPT.eInvoice and FPT.eSign Support Businesses During the XAdES Transition

During the transition period, businesses can contact FPT for guidance on the XAdES support capabilities of their existing digital signature and electronic invoicing solutions, as well as suitable upgrade options.

FPT.eSign is a digital signature solution within the FPT ecosystem that can be integrated with FPT.eInvoice electronic invoicing software.

Information about the XAdES standard and FPT.eSign’s support capabilities is available in the article FPT.eSign Supports the XAdES Standard for Electronic Invoicing.

For guidance on the XAdES transition roadmap and suitable preparation measures, businesses can leave their contact details HERE or contact FPT’s hotline at 1900 636 191.