LibreOffice vs Euro-Office: The Battle for True Digital Sovereignty

Euro-Office, a new European productivity suite forked from ONLYOFFICE and backed by Nextcloud and IONOS, promises self-hosted collaborative editing for governments and organizations. But The Document Foundation (TDF), the nonprofit behind LibreOffice, has raised a critical question about its commitment to open standards—specifically, which document format Euro-Office will use as its native default. Their concern: without a clear embrace of the Open Document Format (ODF), Euro-Office may merely shift dependency from one vendor to another, rather than achieving genuine digital sovereignty for Europe.

What is Euro-Office and why does it claim to be sovereign?

Euro-Office is a web-based office suite developed by Nextcloud and IONOS, forked from the open-source ONLYOFFICE project. It is designed to be self-hosted, meaning organizations and governments can run collaborative document editing on their own infrastructure, without relying on external cloud providers. The project explicitly markets itself as a response to concerns over digital sovereignty—particularly the desire to move away from office software with ties to Russia (ONLYOFFICE is developed by Ascensio System SIA, based in Latvia but with historical roots in Russia). By hosting and controlling the software themselves, European institutions aim to reduce dependence on non-European tech giants. However, TDF argues that sovereignty involves more than just where code runs; it also requires open document formats, open fonts, and continuity of expertise—and that Euro-Office has not yet proven it delivers on those fronts.

What specific question did The Document Foundation ask Euro-Office?

In late March 2025, TDF published an open letter to European citizens and followed up with a public query to Euro-Office: What document format will be used as the native default for creating and sharing documents? The question is central because the default format determines what happens when a user saves a file—if it defaults to OOXML (the Microsoft Office format), then even if the software is hosted in Europe, the format is still controlled by a U.S. corporation (Microsoft). TDF wants Euro-Office to commit to the Open Document Format (ODF), an ISO standard that is royalty-free and governed by an open community, not a single company. TDF stated they received no response, which they publicly noted in a thank-you post to ODF contributors, framing it as a pointed silence.

Why does the choice between ODF and OOXML matter for digital sovereignty?

True digital sovereignty means that a country or institution can control its own data and software without relying on foreign entities for core functionality. OOXML, while widely used, is wholly designed and maintained by Microsoft—a U.S. company. Any office suite that defaults to OOXML is still structurally dependent on Microsoft's decisions about format updates, licensing, and patents. In contrast, ODF is an open international standard (ISO/IEC 26300) developed by a consortium including multiple vendors and public bodies. No single company controls it. Because ODF is fully documented and patent-free, any software can implement it without permission. For European public administrations seeking to break free from lock-in, adopting ODF as the native format ensures that document interoperability is not tied to a specific vendor's roadmap or geopolitical interests.

Has Euro-Office addressed the format question at all?

Partially, but not conclusively. Euro-Office's GitHub repository lists support for ODF alongside DOCX, PPTX, and XLSX—so it does technically handle open formats. However, its FAQ emphasizes “great MS compatibility,” which TDF views as a red flag. Supporting a format and making it the native default are two different things. The native default determines what format is automatically used when a user creates a new document without explicitly choosing. If that default is OOXML, then the majority of users in public bodies will continue to produce MS Office files, perpetuating dependency on Microsoft. Euro-Office has not clarified whether ODF or OOXML will be the default for documents created and shared between European public bodies. TDF's open question remains unanswered, and the silence suggests that Euro-Office may be prioritizing market familiarity over genuine sovereignty.

How does Germany’s ODF mandate affect the debate?

Germany has already passed a law requiring all federal public administrations to use open document standards—specifically ODF—for their official communications. This means that any office suite used by German government agencies must be able to produce ODF natively, not just as an export option. Euro-Office, if it wants to be adopted by German institutions, will have to comply with that legal requirement. TDF's question thus has practical teeth: if Euro-Office cannot commit to ODF as its native default, it may be ineligible for use across large segments of the European public sector. The mandate also sends a signal to other EU countries that may follow suit, making the format issue not just a philosophical debate but a compliance necessity. Euro-Office's silence could be a strategic risk—or a sign that it has not yet decided how to reconcile its MS-compatibility pitch with the legal landscape.

What does The Document Foundation say true digital sovereignty requires?

In its open letter, TDF outlined three pillars of real digital sovereignty: open document formats, open fonts, and continuity of expertise. Open formats ensure that data is not locked into any proprietary system; open fonts prevent typographic dependency on proprietary typefaces; and continuity of expertise means that public bodies must have employees trained to maintain and operate the software themselves, not just contract out support. TDF argues that switching from Microsoft Office to another vendor's suite—even one hosted in Europe—does not automatically grant these elements. For example, if Euro-Office defaults to OOXML and uses proprietary fonts, the dependency simply moves from a U.S. software vendor to a European one, but the data remains in a format controlled by Microsoft. True sovereignty, TDF insists, requires a deliberate commitment to standards that are open, community-governed, and free from any single vendor's influence.