Publishing WG Telco, 2018-07-30: publishing status, implementations, start thinking EPUB4

See minutes online for a more detailed record of the discussions.

Publishing status

A new stable version has been published; a larger community (PBG, I18N, etc) have been asked to review it and comment. Future releases should come more often, e.g., if and when the WebIDL becomes synchronized with the manifest details.


There were discussions about possible test implementations; this may include implementations concentrating on non-packaged use cases (e.g., scholarly papers), traditional ebooks, but also producing some WP-s based on existing content. These implementations should produce feedbacks, raise errors, issues, etc.

Start thinking about EPUB4

The group should start thinking about what EPUB4 will include and do. The discussion was not concentrating on any specific issues yet, nor did it come with resolutions, just a set of first thoughts on the technical aspects as well as the “messaging” aspect of things. Some random thoughts from the discussions:

  • the boundaries of a publications should become more crisp than it is today, that will require technical discussions
  • EPUB4 should be, conceptually, as simple as putting a WP into a zip file—although in reality it is more than that, there may be constraints on the zip structure, just like it is the case in EPUB3:
    • links to file system links is an open issue
    • media type and its inclusion into the file
    • etc.
  • a clear messaging will be needed on what EPUB4 should achieve compared to EPUB3. Some things that came up:
    • most of the content is identical to EPUB3 is identical “except” for a better compatibility with today’s Web (“content is king!”)
    • EPUB4 = EPUB3 + Web Compatibility
    • Web compatibility means that editors/authors/etc can rely on the Web Developers’ community in helping developing content: it is also about the compatibility of people
    • full compatibility with publications that are inherently not packaged, ie, a convergence of traditional ebooks with journals, magazines, single-file publications, scholarly communications, comics, audio books, etc.
      • noting that audio books are naturally part of WP already…
      • we are not talking about converting the EPUB3 market but extending it
  • we have to be realistic, and expect that the EPUB3 and EPUB4 markets will coexist for a while, publishers are slow in moving to new technologies (witness the difficulties of EPUB2 vs. EPUB3 transition)

Clearly food for thoughts and discussions later!

The group decided to take a (Northern Hemisphere) summer break of two weeks; next meeting will be on the 20th of August.

About Ivan Herman

Ivan Herman is the Technical Lead for Publishing@W3C. For more details, see

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