Amazon announced that, after June 28, 2021, Kindle will no longer ingest the MOBI format for reflowable e-books, as well as the derived formats PRC and AZK. This is a turning point for Amazon, who announced this decision as the first step “to simplify the e-book publication process” on its platform.

As for reflowable e-books, publishers will have to use other formats: EPUB, KPF (Kindle Create files) or DOC/DOCX (Microsoft Word files). As stated by Amazon, these rules will be effective both for publishers and for self-publishing authors who provide their e-books on the platform. The MOBI format, anyway, will still be accepted for all fixed-layout e-books.

MOBI and EPUB

The MOBI format was created as a digital publication format by the French company Mobipocket, bought in 2005 by Amazon, that then chose this format for its Kindle devices. Until now, MOBI files were produced starting from publishers’ EPUB files in order to make them available on the Amazon store, a process that will be simplified and sped up by this new choice.

The EPUB format is an open standard for the publication of e-books. It was adopted as the official standard by the International Digital Publishing Forum (IDPF), and now is managed by the World Wide Web Consortium (W3C). EPUB is one of the mainstream format of the digital publishing industry. 

In particular, the EPUB 3 format allows the creation of more accessible contents, providing print impaired readers with fully usable publications. This is possible thanks to a maximized use of the HTML5 semantic tags, the development of ARIA tags (which identify the different parts of the text), as well as the possibility to declare the file’s accessibility level directly inside the e-book’s metadata.

Recently the W3C released the draft of the EPUB Accessibility 1.1. Conformance and Discoverability Requirements for EPUB Publications. This is particularly relevant in light of the forthcoming implementation of the European Accessibility Act.