The future of EPUB3

The future of EPUB3

The EPUB3 standard is an eBook standard from the IDPF, based on web standards such as HTML5 and XML.

This standard was published on October 2011 and today at 2014 has still relatively low adoption rates and even though 3 years have passed, it still did not take over and many publisher still use the former EPUB2 standard. This of course raised many opponent voices against the EPUB3 standard and some even say it is approaching it's death and not relevant any more.

We at Helicon Books still believe this is the standard of the future because of all the options it opens to publishers. With EPUB3, a book can be more then just a book, it can be a whole production with video, audio, interactivity, read aloud (media overlay) and many more. This provides a whole new user experience. However, we still listen to the opponents and in this article I'd like to give my opinion and try to answer the opponents. When I read the opponents I find that in essence they are saying four things:

  • EPUB3 adoption rate is slow therefore it is a dead standard.
  • The standard is very complicated and thus hard to use.
  • There are many reading applications, most of them do not support EPUB3 so we can not read EPUB3.
  • The few compliant reading applications do not support all the standard.

 I tend to agree with some of the above arguments, however despite of this I think EPUB3 is still not dead, so I will try to explain it by answering each of the argument.

1. EPUB3 adoption rate is slow

That is not exactly true, we see more and more publishers stating they are committed to EPUB3. It took a long time until this happened, these statement where made only around 2013, almost two years after the standard was release, and this although many of this publishers where part of the IDPF group who wrote the standard. Why is that? I don't think I can give a definite answer to this question, however in my opinion the reason is argument number 2

2. The standard is very complicated and thus hard to use

This argument is true, the standard is complicated and takes a long time to learn and use. Actually the EPUB3 is not one standard but a collection of standards, we have the Open Container Format (OCF), Open Publication Format (OPF), EPUB3 content documents, HTML5 (Not an IDPF standard but still part of EPUB3), Synchronized Multi Media Interface Standard (SMIL), Canonical Fragment Identifier (CFI) etc. So we can easily see it is complicated. However if we think on all the features this standard try to bring into publications, we can understand it must contain many sub standards.

In fact EPUB3 is just a packaged HTML5 and thus add to HTML5 the Open Publication Format and Open Container Format that where present also in the older EPUB2 standard.

EPUB3 adds many things to the EPUB2 standard and I don't think we can add all these features without creating a complex standard. In order to make things easier, the IDPF decided to break it into some standard documents instead of just one long and complicated standard.

3. There are many reading applications, most of them do not support EPUB3 so we can not read EPUB3

This is true there are many reading applications that does not support EPUB3, however this does not mean we can not read EPUB3. The standard is backward compatible with EPUB2 and thus we can still read EPUB3 documents with EPUB2 compliant reading application, however, we will not be able to take advantage of the new EPUB3 features and we may have few publications we will not be able to read. We will not be able to read Fixed Layout documents that some people wrongly believe this is the only addition of EPUB3.
Most EPUB3 publications are reflowable books and can mostly be read on EPUB2 reading applications.

There are however some cases where we can read a publication in an EPUB2 compliant reading system, but it would look better and should be read in EPUB3 reading system, for example: Hebrew and Arabic books that are written from right to left and paging is done from right to left, or Japanese books that are written top to bottom with right to left paging.

We at Helicon Books create many books in Hebrew and Arabic and thus mainly use EPUB3.

4. The few compliant reading applications do not support all the standard.

From all the above argument, this is the only argument I truly agree with. Unfortunately there are relatively few reading systems (applications) that support EPUB3. Non of them fully support the standard. In my opinion, the main reason for this is the second argument that EPUB3 is a complex standard.

However I think this situation is changing. In 2012 Helicon Books started marketing the world first EPUB3 reading application for Android. After that we set of writing a new application based on the Open Source readium code. During this time we have seen the rise of many new applications and updates to existing applications to support the new standard.

We also take part in the EPUB3 test suite by the IDPF and BISG ( that supplies a test suite for reading systems implementers to test the compliance of their system to the standard. This is also a tool for users to help them choose an EPUB3 compliant system.

I believe we will see more and more EPUB3 compliant reading systems so in the near future this argument will not be true any more.


Although the arguments against EPUB3 are somewhat true, we still need such a standard and we at Helicon Books believe that any other standard that tries to deliver all the features EPUB3 deliver will face the same issues.

In the near future we will see more and more compliant reading systems which will pave the way to more sophisticated books that are more then just a book.

Some people would say we do not need EPUB3 since we have HTML5, this is not true since EPUB3 is essentially HTML5 and add some necessary things like packaging, table of contents etc.

Share this post