Sigil 2.8.5 Adds AVIF and JPEG XL Support
The open-source EPUB editor's latest stable release brings new image formats, a redesigned cropping dialog, and a spec-compliant CSS parser.
Updated on Nov. 6, 2026 in Software
Sigil 2.8.5 has been released as the latest stable version of the open-source EPUB editor. The update adds support for AVIF and JPEG XL images and replaces the outdated CSS parser with a spec-compliant parser based on Lexbor.
Why it matters
Sigil is available on Linux, macOS, and Windows, so the update reaches EPUB authors and editors across all three platforms. The parser replacement and new image format support address longstanding limits in how the editor handles modern EPUB content.
The release swaps the CSS parser for one built on Lexbor, and bulk file additions now use direct file writes with truncation that skip touching the OPF file. The release notes do not quantify how much faster bulk additions run, and no comparative performance figures were published.
The players
Sigil
Sigil is an open-source EPUB editor available on Linux, macOS, and Windows, and it is the software whose 2.8.5 release is the subject of this story.
The details
Sigil 2.8.5 lets users polyfill JPEG XL images in the Preview window through a URL scheme handler, and allows custom Insert Special Characters dialogs via a special_characters.xml file. The TOC Editor now supports multiple selection, and EPUB3 tools control cover metadata creation and removal.
Timeline
November 6, 2026: Sigil 2.8.5 released as the latest stable version
The Tech Race
Sigil's move to a Lexbor-based parser replaces a legacy CSS component with one tied to an established standards-oriented parsing engine. The update also adds AVIF and JPEG XL image support, keeping the open-source EPUB editor aligned with newer image formats.
EPUB authors can now embed AVIF and JPEG XL images and use multiple selection in the TOC Editor when building e-books. Users who maintain custom special characters can define their own Insert Special Characters dialog through a special_characters.xml file.
The takeaway
Authors who build EPUB files with unusual image formats or custom character sets can now handle them directly inside Sigil rather than converting files beforehand. Checking the release notes for the 2.8.5 changes before updating helps identify which workflows are affected.
Further reading
Learn more about the Software tools that power digital publishing and e-book creation.
Source note: This article includes information reported by 9to5Linux.
