Digital sovereignty, or the ability of nations, organisations and individuals to control their own digital destiny, is a fundamental issue of the 21st century. At the heart of this challenge lies a seemingly trivial question: who controls the format of the documents that contain our intellectual property or personal information?

In this context, the standard and open Open Document Format (ODF) – the native format of LibreOffice documents, also supported by other suites – is the fundamental technology for those seeking true digital independence.

Digital sovereignty includes the ability to control access to one’s own information without depending on third parties, to make independent technological choices based on one’s own needs, to ensure independent access to strategic data without depending on the commercial interests of Big Tech, and to maintain this technological self-determination in the face of market consolidation.

When government agencies, businesses, or citizens store their documents in proprietary formats controlled by Big Tech, they surrender part of their sovereignty and depend on these external entities to access their own information.

Why document formats are important for sovereignty

Document formats are infrastructure, which—like roads, power grids, or telecommunications networks—are fundamental to the functioning of modern societies. Consider what happens when strategic documents exist only in formats controlled by a single vendor:

• Vendor Lock-In: Organisations find themselves trapped, unable to switch to alternative software without costly conversion processes and potential data loss.
• Loss of Control: formats can and do change without notice and beyond the control of users, increasing the effect of vendor lock-in.
• Fragility of Access: if the vendor controlling the format changes the format or discontinues support, as was the case with Windows 10, access to documents becomes problematic or impossible.
• Economic Dependency: The cost of the licence required to perform software updates creates a relationship of economic dependency in order to access one’s own data, and effectively transfers ownership of the data to the vendor that controls the format.

Why ODF is the only tool for digital sovereignty

ODF is governed by OASIS, an international standardisation organisation that protects its transparent development, and is published as ISO/IEC 26300-2015 (and soon ISO/IEC 26300-2025). Unlike proprietary formats, ODF specifications are public and can be freely implemented, are developed through a transparent, multi-stakeholder process, are not controlled by a single government or company, and are subject to international standardisation bodies.

This means that governments and companies can participate in defining the format specifications, rather than being forced to passively accept changes imposed by a single vendor based on its commercial strategies.

Thus, ODF specifications allow anyone to create an office suite that natively supports the format and promotes digital sovereignty, without any authorisation, licence fees or fear of legal action, while supporting the local software industry.

ODF enables true interoperability, not only between different software packages, but also between countries, languages and political systems. A document created in Brazil can be opened and edited in India, Germany or Japan using locally developed software. This breaks …

Berlin, 13 November 2025 – LibreOffice 25.8.3, the third minor release of the free, volunteer-supported office suite for personal productivity in office environments, for Windows, MacOS and Linux, is now available at www.libreoffice.org/download. The new version fixes 70 issues compared to the previous release, which came out in October [1].

LibreOffice 25.8.3 is based on the LibreOffice Technology, which enables the development of desktop, mobile and cloud versions – either from TDF or from the ecosystem – that fully supports the two document format standards: the open ODF or Open Document Format (ODT, ODS and ODP), and the closed and proprietary Microsoft OOXML (DOCX, XLSX and PPTX). Products based on the LibreOffice Technology are available for all major desktop operating systems (Windows, macOS, Linux and ChromeOS), mobile platforms (Android and iOS) and the cloud.

For enterprise-class deployments, TDF recommends the LibreOffice Enterprise optimized versions from ecosystem companies, with dedicated value-added features and other benefits such as SLAs and security patch backports for three to five years (www.libreoffice.org/download/libreoffice-in-business/).

English manuals for the LibreOffice 25.8 family are available for download at https://books.libreoffice.org/en/. End users can get first-level technical support from volunteers on user mailing lists and Ask LibreOffice website: ask.libreoffice.org.

Downloading LibreOffice

All available versions of LibreOffice for the desktop can be downloaded from the same website: www.libreoffice.org/download/. To improve the interoperability with Microsoft 365, we suggest installing the Microsoft Aptos font from this web page: learn.microsoft.com/en-us/typography/font-list/aptos.

LibreOffice enterprise and individual users can support The Document Foundation and the LibreOffice project by making a donation: www.libreoffice.org/donate.

[1] Fixes in RC1: wiki.documentfoundation.org/Releases/25.8.3/RC1. Fixes in RC2: wiki.documentfoundation.org/Releases/25.8.3/RC2.

Last Saturday, November 8, I have managed a workshop at SFScon on Font management for document interoperability in LibreOffice. The workshop aimed to demonstrate how to configure and manage the LibreOffice font replacement feature, one of the key elements of document interoperability. Although font replacement on the fly is a long-standing LibreOffice feature, it is rather unknown and must be configured and managed properly in order to substitute proprietary fonts, which are standard on Windows and macOS and have been used as a lock-in tool for years, with metrically compatible free fonts.

In September 2020, I wrote the blog post LibreOffice Tips & Tricks: Replacing Microsoft Fonts, which explained how to create a Font Replacement Table (available in Tools > Options > LibreOffice > Fonts) to instantly replace Microsoft’s proprietary fonts with metrically equivalent free fonts, available from Google Fonts and other websites. However, I recommend using Google Fonts for legal compliance, as they provide the font, licence and all other documents from the font designer. This post prompted several responses and inspired Jean-François Nifenecker, a volunteer contributor, to develop the FontsSubstTableExporter extension, which creates an extension embedding the font’s replacement table for easy duplication or backup, as well as the resulting FontSubstTable, which sets the font’s substitution table values.

During the webinar, I used a short LibreOffice Impress presentation to help the audience follow my talk more easily:

I opened the webinar by showing the 2020 blog post and its associated font replacement table. I then presented the updated table, as Spartan — one of the free fonts — has evolved into League Spartan. I also explained how the situation has changed radically since 2020, as Microsoft has deprecated ClearType fonts (Calibri, Candida, Candara, Consolas, Constantia, Corbel and Segoe for Western languages) and now uses Aptos as the default font for Western languages. Although Aptos is Microsoft proprietary, it has a weaker licence which only prohibits redistribution. As such, it can be downloaded and installed by all users (including Linux users) provided the download is from the official Microsoft Aptos Page.

I also announced that, ideally before the release of LibreOffice 26.2 in February 2026, I will update the FontSubstTable extension to include all Microsoft proprietary fonts with restrictive licences. These are fonts that require replacement as they cannot be installed by Linux users or those without a Microsoft Windows or Microsoft 365 licence. I will also try to generate additional FontSubstTable extensions for the most commonly used fonts in DOCX, XLSX and PPTX files. Thanks to AI, I now have access to a list of these fonts in just a few seconds, which would have taken me weeks to compile manually. These extensions will be available for general use and for specific verticals, such as visual design.

Digital documents in proprietary formats often become inaccessible within a few years due to undocumented changes to the XML schema that are intentionally employed for lock-in purposes. To avoid this problem, it is advisable to use the Open Document Format (ODF) not only for everyday tasks, but also for long-term storage. This ensures that documents remain accessible for years or even generations.

Without this approach, government documents, academic research, legal documents and corporate archives risk becoming true digital orphans — files that exist, but cannot be read. This is not so much because the software that created them is obsolete, but because the XML schema has been modified to make the files readable by a specific version of a single software program. However, the layering of changes makes them unreadable by any software in the long term.

Why is ODF suitable for archiving?

ODF (ISO/IEC 26300 and subsequent versions) is an open standard, managed transparently by OASIS. Its development process and specifications are documented and publicly accessible, unlike proprietary formats, where the process is undocumented and the ISO/IEC specifications do not reflect the reality of the format. This means that even if the current software disappeared, developers could create new programmes compatible with the standard to handle the files and access their content.

Furthermore, ODF files are compressed archives (ZIP) containing XML files based on a schema that can be easily read by non-technical users, enabling anyone to extract and interpret the content. This transparency of format is a fundamental element of its archival value. In contrast, the XML schema of proprietary files is intentionally designed to be unreadable. In this sense, it is a perfect example of how a language created for simplification, such as XML, can become a subtle lock-in tool if used contrary to its nature.

Finally, ODF maintains strong backwards compatibility between versions. This means that all files created with ODF 1.0 in 2005 — immediately after standardisation by OASIS — can be opened without issue by applications released in 2025. This stability is intentional; the format was designed with long-term preservation in mind.

Best practices for archiving in the ODF format

Although newer versions add functionality, the best option for long-term archiving is to use a version recognised by ISO/IEC, such as ODF 1.2 (ISO/IEC 26300-1:2015) or, in the near future, ODF 1.3 (ISO/IEC 26300:2025). This is because it is mature and well documented, and will remain compatible for decades, offering an excellent balance between functionality and breadth of support.

For documents where faithful visual reproduction is important, it is advisable to embed fonts in ODF files to avoid font substitution issues when files are opened years later in a different environment to the one used to create them.

Additionally, all resources related to the documents (images, graphics, etc.) should be embedded in the ODF file rather than linked externally because external links are at risk of breaking over time if the original file is moved, which could …

Love LibreOffice? Join the project and help to make it even better – get involved in the Month of LibreOffice, November 2025! Over the next four weeks, hundreds of people around the world will collaborate to improve the software – and you can help them. There are many ways to get involved, as you’ll see in a second.

And best of all: everyone who contributes to LibreOffice in November can claim a cool sticker pack, and has the chance to win extra LibreOffice merchandise such as mugs, hoodies, T-shirts, rucksacks and more (we’ll choose 10 participants at random at the end):

How to take part

There are many ways you can help out – and you don’t need to be a developer. For instance, you can be a…

• Handy Helper, answering questions from users on Ask LibreOffice. We’re keeping an eye on that site so if you give someone useful advice, you can claim your shiny stickers. We also monitor the users@ mailing list.

• First Responder, helping to confirm new bug reports: Go to our Bugzilla page and look for new bugs. If you can recreate one, add a comment like “CONFIRMED on Windows 11 and LibreOffice 25.8.2”.

• Drum Beater, spreading the word: Tell everyone about LibreOffice on Mastodon, Bluesky or X (Twitter)! Just say why you love it or what you’re using it for, add the #libreoffice hashtag, and at the end of the month you can claim your stickers.

• Globetrotter, translating the user interface: LibreOffice is available in a wide range of languages, but its interface translations need to be kept up-to-date. Or maybe you want to translate the suite to a whole new language? Get involved here.

• Code Cruncher, contributing source code: The codebase is big, but there are lots of places to get involved with small jobs. See our Developers page on the website and this page on the wiki to get started.

• Docs Doctor, writing documentation: Whether you want to update the online help or add chapters to the handbooks, here’s where to start.

We’ll be updating this page every few days with usernames across our various services, as people contribute. So dive in, get involved and help make LibreOffice better for millions of people around the world – and enjoy your sticker pack at the end as thanks from us! And who knows, maybe you’ll be lucky enough to win bonus merch as well…

So let’s get going! We’ll be posting regular updates on this blog and our Mastodon, Bluesky and X (Twitter) accounts over the next four weeks – stay tuned…

Open Document Format (ODF) is an open standard for office documents – texts, spreadsheets, presentations and more – that is flexible and interoperable. As with any other digital format, its security is a key concern, as ODF files often contain sensitive information that, without adequate protection measures, can be exposed, tampered with or tracked.

This post analyses how ODF handles security, focusing on encryption, digital signatures and metadata management: three features that protect documents from prying eyes and tampering.

Encryption: content locking

ODF supports file-level encryption using standard algorithms. When you save an ODF document with a password, the content is compressed and then encrypted using AES (Advanced Encryption Standard), typically with a 256-bit key.

Here’s what happens behind the scenes:

1. The document content (the XML file) is compressed.
2. A random salt (a sequence of bits used together with a password as input to a one-way function) and an initialisation vector (IV), which is a block of bits of a predefined length, are generated.
3. A key is derived from the password using PBKDF2 (Password-Based Key Derivation Function 2). The key is a string of data used with an algorithm to encode (encrypt) and decode (decrypt) the text, transforming it from plain text to unreadable text.
4. AES encrypts the content using this key.

This is encryption based on open and verified algorithms, sufficiently strong when implemented correctly, whose security depends largely on the strength of the password. Users should therefore always use long, unique passwords, preferably created by a password generator.

Unfortunately, not all applications that support the ODF format implement encryption in the same way, with possible repercussions on interoperability.

Digital signatures: who modified the document?

Digital signatures guarantee authenticity and integrity, and show who created or modified the ODF file, and whether it has been modified by another user since its creation.

How it works:

1. ODF uses XML digital signatures.
2. A cryptographic hash of the document’s content is created (a fixed-size digital fingerprint of data, created by a one-way algorithm that is almost impossible to reverse).
3. This hash is signed with the signer’s private key (a secret code, similar to a password, used to encrypt and decrypt data and digitally sign transactions).
4. The signature is stored in “META-INF/documentsignatures.xml”.

This makes it possible to verify the origin of the document, but verifying signatures requires access to the signer’s public key or certificate. If the workflow involves multiple people, multiple signatures are supported. Any changes to the file after signing invalidate the signature.

Unfortunately, not all office suites that support ODF consistently display or validate signatures.

Metadata management: a potential information leak

Metadata can unintentionally disclose various information, including sensitive information such as usernames, file paths, software versions, timestamps (creation and save dates), and even content revision history.

What does metadata contain?

1. Author name, change history, and save times.
2. Custom properties, such as project codes or internal comments.
3. Application-specific data embedded in namespaces.

Malicious actors can extract metadata for social engineering, document tracking, or profiling purposes. To …

Here’s our summary of updates, events and activities in the LibreOffice project in the last four weeks – click the links to learn more…

• We started the month by posting the LibreOffice Podcast, Episode #5 –Accessibility in Free and Open Source Software, with Michael Weghorn and Mike Saunders. Watch it below – or on PeerTube.

• Markdown support is coming to LibreOffice! This is just one of the projects from the Google Summer of Code 2025, and should be included in our next major release, LibreOffice 26.2, due in February next year.

• In October, we had two updates to the software: LibreOffice 25.8.2, and LibreOffice 25.2.7. The latter is the final update to the 25.2 branch, so after this, all users are recommended to upgrade to the 25.8 branch.

• It’s the End of 10! Yes, in October, Microsoft ended official support for Windows 10. This leaves users who want to continue using the operating system with few alternatives — especially if they have an old PC that is not compatible with Windows 11’s demanding hardware requirements — other than buying a new PC. But we a posted about 10 reasons to switch to Linux – and, of course, many desktop Linux distributions ship with LibreOffice.

• Lots of people ask us about LibreOffice’s compatibility with Microsoft Office/365 documents. We think our compatibility is very good (and always improving, as more people send us documents to test), but the format is extremely difficult to work with, as our posts about the DOCX and PPTX formats explain. (Of course, ideally we’d all be using the Open Document Format, regardless of the software we prefer! And here’s how to make your ODF documents more accessible.)

• The Document Foundation is the small (15-person) non-profit organisation that coordinates the LibreOffice project and community. And we’re expanding! In October, we posted two new positions: Paid Developer working on Base (application deadline already over) and Paid Developer focusing on scripting support (application deadline November 17).

• Then we provided an update on LibreOffice 64-bit progress, and support for Amazon Linux 2023.

• Our Nepalese community is organising an event called the LibreDots Unconference 2025 in Kathmandu. More details to follow – stay tuned to this blog!

• Meanwhile, the Libreitalia Conference 2025 was organized by Marco Marega – a LibreItalia and TDF Member – in Gradisca d’Isonzo, near the border with Slovenia.

• Then we posted the outcome and conclusions of the VI Latin American LibreOffice Congress, which was held in Habana, Cuba, from October 6 to 9.

• And our final event report was from LinuxDays 2025 in Prague, where we had a stand with stickers, flyers and a quiz about LibreOffice.

Keep in touch – follow us …

Berlin, 30 October 2025 – The Document Foundation announces the release of LibreOffice 25.2.7, the final maintenance release of the LibreOffice 25.2 family, available for download at www.libreoffice.org/download [1]. Users of LibreOffice 25.2.x should update to LibreOffice 25.8.x, as LibreOffice 25.2.x is approaching the end of its support period.

LibreOffice 25.2.7 is based on the LibreOffice Technology, which enables the development of desktop, mobile and cloud versions – either from TDF or from the ecosystem – that fully supports the two document format standards: the open ODF or Open Document Format (ODT, ODS and ODP), and the closed and proprietary Microsoft OOXML (DOCX, XLSX and PPTX).

Products based on the LibreOffice Technology are available for all major desktop operating systems (Windows, macOS, Linux and ChromeOS), mobile platforms (Android and iOS) and the cloud.

For enterprise-class deployments, TDF recommends a LibreOffice Enterprise optimized version from one of the ecosystem companies, with dedicated value-added features and other benefits such as SLAs and security patch backports for three to five years (www.libreoffice.org/download/libreoffice-in-business/).

English manuals for the LibreOffice 25.2 family are available for download at books.libreoffice.org/en/. End users can get first-level technical support from volunteers on the user mailing lists and the Ask LibreOffice website: ask.libreoffice.org.

Downloading LibreOffice

All available versions of LibreOffice for the desktop can be downloaded from the same website: www.libreoffice.org/download/.

LibreOffice users, free software advocates and community members can support The Document Foundation and the LibreOffice project by making a donation: www.libreoffice.org/donate.

[1] Fixes in RC1: wiki.documentfoundation.org/Releases/25.2.7/RC1. Fixes in RC2: wiki.documentfoundation.org/Releases/25.2.7/RC2.