Improve ODF support

[juliusknorr]

New files default to OOXML formats (.docx, .xlsx, .pptx), ODF editing has known fidelity gaps, and there is no admin-level option to enforce ODF as the default. This initiative tracks the work to make ODF a fully supported, first-class format in Euro-Office.

Current state

ODF is the ISO-standardised open document format championed by LibreOffice and mandated by public administrations across the EU. Euro-Office is positioned as an open, sovereign alternative to proprietary office suites, making robust ODF support a strategic requirement, not just a feature request.

The current state inherited from upstream has several known shortcomings:

• Default format is OOXML. New files are created as .docx/.xlsx/.pptx with no admin or user setting to change this default to ODF. This has been a long-standing community request upstream.
• ODF files open read-only in some configurations. Despite enabling ODF editing in settings, .odt, .ods, and .odp files can open in read-only mode.
• Fidelity gaps when round-tripping ODF. Formatting, styles, and certain features are lost or altered when opening and re-saving ODF documents, making reliable ODF workflows impractical.
• No ODF default on mobile. The mobile editors do not support saving in ODF — all saves are forced to OOXML regardless of the source file format.
• ODF template formats (.ott, .ots, .otp) are poorly handled. Template types are not correctly associated and may not open in the editor at all without manual workarounds.

References

• Upstream community thread: Make ODF a first-level citizen in ONLYOFFICE
• Upstream PR (experimental ODF default): onlyoffice-nextcloud#886
• Upstream issue (configure ODF creation): onlyoffice-nextcloud#224
• Upstream issue (ODF opens read-only): onlyoffice-nextcloud#811

Next steps

• Add admin setting for ODF as default new file format (Euro-Office/nextcloud-onlyoffice)
• Fix ODF files opening in read-only mode when ODF editing is enabled (Euro-Office/nextcloud-onlyoffice)
• Research and identify gaps in ODF support for different file formats

Work packages can be tracked as subtasks