W3C Invites Implementations of EPUB 3.4, EPUB Reading Systems 3.4 and EPUB Accessibility 1.2
The W3C Publishing Maintenance Working Group invites implementations of the following three Candidate Recommendation Snapshots:
- EPUB 3.4: EPUB® 3 defines a distribution and interchange format for digital publications and documents. The EPUB format provides a means of representing, packaging, and encoding structured and semantically enhanced web content — including HTML, CSS, SVG, and other resources — for distribution in a single-file container. This specification defines the authoring requirements for EPUB publications and represents the fourth major revision of the standard.
- EPUB Reading Systems 3.4: This specification defines the conformance requirements for EPUB 3 reading systems — the user agents that render EPUB publications.
- EPUB Accessibility 1.2: This specification specifies content conformance requirements for verifying the accessibility of EPUB® Publications. It also specifies accessibility metadata requirements for the discoverability of EPUB publications.
Comments are welcome via GitHub issues by 19 October 2026.
Note: The Candidate Recommendation phase indicates that the Working Group considers this version of the documents to be technically final with the testing phase being all that is left before it is published as a Recommendation.