Euro-Office and Digital Sovereignty: 10 Key Questions Answered

When Nextcloud and IONOS launched Euro-Office in early 2025, it was hailed as a step toward European digital sovereignty—a self-hosted, web-based office suite designed to reduce reliance on non-European tech giants. But the announcement quickly drew scrutiny from The Document Foundation (TDF), the nonprofit behind LibreOffice. TDF questioned whether Euro-Office truly delivers on its promise, especially regarding document formats and independence. This listicle unpacks the 10 most critical aspects of the debate, from native formats to real sovereignty.

1. What Is Euro-Office?

Euro-Office is a new European productivity suite developed by Nextcloud and IONOS. It is a fork of ONLYOFFICE, but it’s designed specifically for organizations and governments that want collaborative document editing on their own infrastructure. The suite is self-hosted and web-based, targeting users who need control over their data. Its creation was motivated by concerns about digital sovereignty, especially after noticing that ONLYOFFICE had ties to Russia. By moving the software to European control, the project aims to offer a trustworthy alternative for public bodies and businesses.

Euro-Office and Digital Sovereignty: 10 Key Questions Answered — Source: itsfoss.com

2. Why Was Euro-Office Created?

The primary driver behind Euro-Office was the desire to break away from office suites with links to non-European jurisdictions, particularly Russia. The original ONLYOFFICE had raised red flags because its parent company, Ascensio System SIA, is registered in Latvia but with development roots in Russia. For European institutions wary of geopolitical entanglements, this was problematic. Euro-Office was forked to eliminate those ties and provide a solution that could be hosted on European servers, under European law. However, TDF argues that simply switching vendors doesn’t automatically guarantee sovereignty—the underlying technology choices matter even more.

3. LibreOffice’s Core Question: What’s the Native Format?

Shortly after Euro-Office’s launch, TDF asked a simple but powerful question: what document format would Euro-Office use as its native default? The answer is critical because the native format determines how files are created, saved, and shared by default. If Euro-Office defaults to OOXML (Microsoft’s format), it remains structurally dependent on decisions made in Redmond, USA. TDF received no reply, which it interpreted as a troubling silence. The organization then issued a thank-you post to ODF contributors, subtly criticizing Euro-Office’s lack of transparency.

4. TDF’s Open Letter to European Citizens

In late March, TDF published an open letter to European citizens, arguing that digital sovereignty is not a simple matter of switching office software vendors. Real sovereignty, TDF said, requires open document formats, open fonts, and continuity of expertise—none of which come automatically with vendor replacement. The letter stressed that a nation’s digital independence depends on control over its data and the standards used to exchange it. Without that, even software hosted in Europe can be a Trojan horse for external control.

5. ODF vs. OOXML: The Format War

At the heart of the controversy is the battle between ODF (Open Document Format) and OOXML (Office Open XML). ODF is an ISO standard developed openly by a consortium of organizations. No single company controls it, making it ideal for sovereign use. OOXML, by contrast, is designed and controlled entirely by Microsoft. Any office suite that defaults to OOXML compatibility—even if it’s hosted in Europe—remains tethered to Microsoft’s technical decisions. TDF wants Euro-Office to commit to ODF as its native format to truly break from U.S. dependence.

6. Euro-Office’s Silent Stance on Formats

Despite TDF’s public query, Euro-Office has not clarified whether it will default to ODF or OOXML. Its launch press release made no mention of ODF as a native format. This omission raised eyebrows because any European public body using the suite would need assurance that its documents are not locked into a proprietary standard. TDF asked directly whether Euro-Office would make ODF the default for documents created and shared between public bodies. So far, no official response has been given.

7. What Euro-Office’s GitHub Actually Shows

Euro-Office’s GitHub repository does list ODF formats alongside DOCX, PPTX, and XLSX. So it’s not that the suite excludes open formats entirely—it supports them. However, supporting a format and making it the native default are two very different things. The native format is the one used automatically when a user creates a new document. If ODF is merely supported but not default, users may inadvertently create files in OOXML. This subtle distinction can have massive implications for long-term interoperability and independence.

8. The ‘Great MS Compatibility’ Problem

Euro-Office’s FAQ frames the entire project around “great MS compatibility.” While this may appeal to organizations migrating from Microsoft Office, it reinforces dependence on Microsoft’s ecosystem. TDF warns that this approach simply shifts the dependency from proprietary software to proprietary file formats. Trusting a European vendor to maintain compatibility with U.S.-controlled standards is not the same as owning your data. Real sovereignty, TDF argues, requires native use of open standards that no single vendor can manipulate.

9. Germany’s ODF Mandate Sets a Precedent

Germany has already mandated ODF for all federal public sector documents by law. This legal requirement means that any office suite used by German public bodies must default to ODF. Euro-Office cannot sidestep this if it wants to serve German institutions. But the suite’s current ambiguity suggests it may be trying to please both sides—offering ODF support while still emphasizing compatibility with Microsoft formats. Over time, this dual approach could create confusion and hinder the very sovereignty that Euro-Office claims to promote.

10. The Broader Sovereignty Question

TDF’s question is not just about Euro-Office—it’s about what digital sovereignty truly means in practice. Moving a server from the U.S. to Europe is a step, but real independence comes from open standards, open source code, and community governance. Euro-Office’s silence on native formats, combined with its emphasis on “great MS compatibility,” raises doubts about its commitment to European values. As the debate continues, institutions must ask themselves: are they swapping one dependency for another, or are they building a genuinely sovereign digital future?

Conclusion: The Euro-Office project represents an important attempt to give European institutions more control over their productivity tools. However, as The Document Foundation has pointed out, sovereignty is not achieved by simply relocating software—it requires deliberate choices about standards and defaults. Without a clear commitment to ODF as the native format, Euro-Office risks perpetuating the very dependencies it aims to break. The coming months will reveal whether the project will address these concerns or remain silent. For now, the ball is in Euro-Office’s court.