This comes from that dusty corner of the literary universe where we store things that may or may not affect you, and if they do affect you, it probably won’t be too much of a change, but it’s good to have this stowed there in case you ever need it….
As of June 28, 2021, Amazon’s Kindle Direct Publishing program (KDP) will no long accept MOBI files. Now, when authors want to publish through KDP, they can upload Word docs, PDFs, EPUB, or MOBI files, but come June, we’ll MOBI no more. PRC or AZK formats also will no longer be accepted.
If you’ve already uploaded a MOBI file to publish a book, don’t worry, nothing needs to be done (unless you want to make changes to that book, in which case, you’ll need to upload a different file format after June 28):
Instead, we ask publishers to use EPUB, KPF (Kindle Create files), or DOC/DOCX (Microsoft Word files) files for reflowable eBooks. Please note MOBI files are still accepted for fixed-layout eBooks.
But you may not want to do that if you want to make your e-book available on the Barnes & Noble Nook, for example, or Kobo, which both prefer EPUB or PDF files (although they’ll take MOBI, for now at least).
While plenty of authors simply upload their Word docs to KDP and hope for the best, there are plenty of reasons to splurge for a professional designer to prepare your book for e-publishing. The difference between reading a PDF on a Kindle, for example, or reading an e-book presented in the dynamic format of an EPUB, is dramatic. Preparing your book correctly means readers will have all the functionalities at their fingertips that e-book readers have come to expect, including jumps, scrolling, etc. Just as it does with printed books, the product ultimately matters. Amazon’s axing MOBI just makes it that much easier to prepare one single EPUB file and use that file to upload across platforms.