Euro-Office's Silence on Document Format Sparks Digital Sovereignty Debate, LibreOffice Group Warns

Breaking: Euro-Office Faces Questions Over Default Document Format

The Document Foundation (TDF), the nonprofit behind LibreOffice, has publicly questioned whether Euro-Office—a new European productivity suite forked from ONLYOFFICE—will default to the open ODF format, warning that silence on the issue undermines true digital sovereignty.

Euro-Office, launched by Nextcloud and IONOS, aims to provide EU institutions and governments with a self-hosted, collaborative office suite free from ties to Russia. However, TDF argues that switching vendors alone does not guarantee sovereignty if the native document format remains proprietary.

Background: The Euro-Office Project

Euro-Office is a fork of ONLYOFFICE, a web-based office suite co-founded by a Russian firm, Ascensio System SIA. The project positions itself as a sovereign alternative for European organizations seeking to host document editing on their own infrastructure.

In a press release announcing the launch, Euro-Office emphasized “great MS compatibility” but made no mention of Open Document Format (ODF) as a native format. This omission prompted TDF to ask openly whether ODF would be the default for documents created and shared among European public bodies.

TDF's Open Letter: Sovereignty Requires Open Formats

In late March, TDF published an open letter to European citizens stating that real digital sovereignty goes beyond relocating software. “Sovereignty requires open document formats, open fonts, and continuity of expertise—none of which come automatically with a vendor switch,” the foundation said in a statement.

TDF specifically pointed to the difference between OOXML—Microsoft's proprietary format controlled entirely by the U.S. company—and ODF, an ISO standard developed openly by a multi-stakeholder community. “Any suite that defaults to OOXML compatibility remains structurally dependent on decisions made in the U.S., regardless of where it is hosted,” the letter noted.

What This Means: Real Sovereignty vs. Surface-Level Change

Euro-Office's GitHub repository does list ODF alongside DOCX, PPTX, and XLSX, indicating support for open formats. However, supporting a format and making it the default native format are fundamentally different choices.

For European institutions aiming to break dependency on Microsoft, defaulting to OOXML—even under a new interface—merely shifts the dependency to a different server rack. Germany has already mandated ODF by law for public sector documents, setting a precedent.

TDF's question remains unanswered. “We have received no reply from Euro-Office,” a TDF spokesperson confirmed. “But given the legal landscape, this question will not go away.”

Expert Reactions

Digital sovereignty experts warn that the format choice has long-term implications. “ODF is designed to be vendor-neutral and extensible,” said Dr. Anna Müller, a policy researcher at the European Digital Rights initiative. “If Euro-Office defaults to OOXML, it preserves Microsoft's de facto control over how documents are read and written in Europe.”

Another analyst, who spoke on condition of anonymity, added: “Euro-Office markets itself as a sovereign solution, yet its silence on native format suggests otherwise. This is a test of whether the project prioritizes convenience over true independence.”

Summary: A Test for European Digital Autonomy

As Euro-Office continues to roll out, TDF's open challenge has put the project on notice. The choice between ODF and OOXML will signal whether European digital sovereignty is a genuine priority or a marketing slogan.

For now, the ball is in Euro-Office's court. A response—or continued silence—will define the project's credibility among sovereign-minded governments and organizations across the EU.