No matter how hard competitors try, Kindle e-readers remain among the most popular in the world. A major factor in this is their seamless integration with Amazon’s vast library of e-books, making it incredibly convenient for users to buy and read books directly from the platform.
However, there has always been one frustrating limitation—Kindle devices have traditionally supported a very restricted set of formats. If we exclude image files, Kindles could only handle TXT, Microsoft Word documents (DOC), and Amazon’s proprietary e-book format, commonly known as MOBI (with file extensions like .azw or .mobi, depending on the version). This is where competitors have tried to outdo Amazon by offering support for a wide variety of formats. But in reality, do we even need an excessive number of formats?
The world of e-books has long since settled on a few standard formats. In the post-Soviet space, the most popular format is FB2 (FictionBook), which isn’t supported by every device but has always been natively handled by PocketBook readers. Meanwhile, the global leader for e-books is ePub, which offers far superior formatting and layout capabilities compared to FB2. An alternative to ePub was meant to be FictionBook’s newer version, FB3. However, it closely resembled ePub in many ways and never gained significant adoption. It has remained in an “experimental” status for years and seems likely to stay that way.
As a result, the e-book format landscape essentially boiled down to three main options, plus one extra. I consider PDF to be the fourth (+1) format. Originally designed not for e-books but for fixed-layout documents, PDFs are ideal for publications where precise text and image placement is crucial. This is useful for certain types of books (ensuring that the reader sees the content exactly as intended for print), but it severely limits readability options—since you can only zoom in or out, with no control over font size and type or text reflow.
Specifically for e-books, the remaining formats were FB2 (Russian region), ePub (global), and MOBI (global, proprietary Amazon format).
If you read books on a Kindle and purchase them exclusively from Amazon, then e-book formats probably never concerned you. However, if you use other e-book stores, you always had to choose the right format for your e-book reader. For example, the Russian retailer Litres has always allowed users to download purchased books in MOBI format specifically for Kindle owners.
But suddenly—just like that!—an era has ended. A few weeks ago, Amazon sent out an email to all users stating that MOBI is now considered obsolete and will no longer support the latest features of Kindle. However, they didn’t explicitly mention what would replace it. Instead, they announced some “good news”—Kindle readers (including mobile and PC apps) will now fully support the ePub format.
So, essentially, Amazon has admitted that they consider ePub to be a perfectly suitable format, they will no longer support their own MOBI, and new books… well, you can draw your own conclusions. Personally, I suspect that the entire Kindle library will gradually be converted to ePub, and Amazon will adopt it as their primary format moving forward. And that makes sense: if there’s already a globally recognized, professionally established format that even supports Amazon’s cherished DRM features (digital content protection), why waste resources inventing a proprietary alternative?
MOBI will still be supported for some time, but Amazon plans to completely phase it out by the end of 2022.
Overall, this is great news. MOBI was indeed an outdated format that survived solely because of Amazon. Meanwhile, ePub allows for formatting options that even FB2 can’t achieve (see my article Litres: Differences Between ePub and iOS.ePub). I’ve also been gradually shifting towards reading more books in ePub format. Fewer variations mean fewer headaches.
But what’s curious is what finally pushed Amazon to take this step. For years, they seemed unconcerned about their proprietary format—and now, all of a sudden, here we are.
