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.

That dumpling can groove.

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