After June 28, 2021, we will no longer support MOBI files when publishing | Hacker News Reader

After June 28, 2021, we will no longer support MOBI files when publishing

kdp.amazon.com

28 pointsdavidgerard11 comments

The page says this is specific to reflowable text ebooks.

Still, I’m confused. Does this mean that plain text files will be the only way to publish reflowable text ebooks to Kindle EInk ereaders? That seems very odd.

The same page clarifies that EPUB, docx, and EPUB creation flows are supported/recommended... and yes, there's HTML and RTF reflowable flows.

If you look at the rightmost column, none of those mention EInk ereader support, only app support.

Sure, but the rightmost column is broken. e.g. It says that KPF/Kindle Create is not supported by EInk readers.

What’s the significance of dropping MOBI? I generally only hear of ebooks released as ePubs, although Ive seen MOBI files around.

I suppose the significance is that there is now only one other competitor to Amazon's format?

MOBI is, and always has been, the format used by Kindle eBooks. (Amazon bought the creator of the format, MobiPocket, in 2005, shortly before launching Kindle.)

The prevalence of MOBI files today is mostly down to people ripping purchased Kindle books off their devices and releasing them to piracy.

The current file format for Kindle purchases, AZW, is just MOBI + DRM. If you strip out the DRM / customer fingerprint, you’re left with a MOBI file. So a large percentage of ripped books on e.g. LibGen will be in MOBI, even though the source was AZW. You can’t remove the identifying fingerprint of the purchaser without also removing the DRM entirely; so pirates do both.

The significance here is essentially that Kindle apps/devices will no longer willingly import+load+display pirated books originally ripped from the Kindle store. Because, at this point, that’s what 99.9% of MOBI files are.

But this announcement only applies to publishing. Taking a mobi from Libgen and sending it to my Kindle via mail shouldn't be affected at all by this?

Or copy via USB?

> The current file format for Kindle purchases, AZW, is just MOBI + DRM.

Not these days it isn't. They built a custom format to support additional features some time ago, KFX[1].

[1] https://wiki.mobileread.com/wiki/KFX

Quite a lot of AZW are really ePub inside. Kindle accepts ePub just fine.

This means self-publishers will often just do an ePub, because that gets them onto everything without extra work.

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