Why book is imported as an KFX-ZIP? (new issue)

[Parriss]

Not sure if this is the correct form. (If I’m in the incorrect form please direct me to the correct one -Thanks)

This is the issue:
Yesterday I bought two books on Amazon published in September 2025 and the other August 2025; downloaded them to my Kindle (11th gen/ ver. 5.18.5.0.1). This is my first purchase with the new update (automatically updated/cannot locate a way to disable this function)

Calibre, version 8.12 / all plugins are up to date (Package KFX 2.26.2 / KFX input same)
DeDRM plugin (10.0.9)
Kindle serial number is set correctly in the plugin config.
Windows 11 (a friend is running Windows 10 and has this same issue, same gen Kindle/book pub. July 2025)

When ‘Add books to library’ in calibre the book appears as an KFX-ZIP even though when looking on the devise download file root it is listed as an KFX file.

When the book is ‘dragged and dropped’ it also appears as an KFX-ZIP in calibre.

I (we) do not understand why it appears as a KFX-ZIP file.

Do I (we) need different plugins?
Is my (our) plugin KFX outdated (although I (we) did the newest update when it became available)
Do I (we) need to find an older version to run on the Kindle? (if this is the case, please direct to where this may be located and how to install it – please & thanks)
I have seen calibre, version 8.5.0 mentioned but can only locate 8.12 (may be v.8.50 is for mac)

I know that the KFX-ZIP cannot be converted.
But tried it anyway and got
Cannot convert....
This book is locked by DRM.

How to stop Calibre from importing/displaying the book as an KFX-ZIP file?
Thanks

[Sirtel]

The latest Kindle update disabled the ability to remove the DRM. There's really nothing else to do but

1) downgrade your Kindle firmware (only possible with jailbroken Kindles), or

2) get an older Kindle no longer receiving updates, or

3) wait until someone figures out a way to get around this latest development (might never happen).

I'd say go for the option 2, unless your Kindle is jailbroken.

Changing calibre and plugin versions won't help, it's a Kindle firmware issue.

[JSWolf]

Originally Posted by Sirtel

The latest Kindle update disabled the ability to remove the DRM. There's really nothing else to do but

1) downgrade your Kindle firmware (only possible with jailbroken Kindles), or

2) get an older Kindle no longer receiving updates, or

3) wait until someone figures out a way to get around this latest development (might never happen).

I'd say go for the option 2, unless your Kindle is jailbroken.

Changing calibre and plugin versions won't help, it's a Kindle firmware issue.

There is a way around this, But it needs K4PC 2.8.0 (I think that's the version) and it needs to be done for each eBook. So really, it's not all that convenient. I'm sticking to my Kindle Touch way of doing it. I mostly get KF8 with some Mobi.

[jhowell]

Originally Posted by Sirtel

…

3) wait until someone figures out a way to get around this latest development (might never happen).

I'd say go for the option 2, unless your Kindle is jailbroken.

Option 3, using a Kindle on the latest firmware, if it is ever developed is also likely to require a jailbroken Kindle because it will need to make use of a secret stored in location on the device that is otherwise inaccessible.

[Parriss]

Thank you everyone.

You all have been very helpful.
I will now look into accruing an older device.

The company wonders why it gets a bad rap.

[JSWolf]

Originally Posted by Parriss

Thank you everyone.

You all have been very helpful.
I will now look into accruing an older device.

The company wonders why it gets a bad rap.

There's a much better solution. Stop buying eBooks from Amazon and go buy them from Kobo. You can price match Amazon at Kobo.

[Sirtel]

Originally Posted by JSWolf

There's a much better solution. Stop buying eBooks from Amazon and go buy them from Kobo. You can price match Amazon at Kobo.

Only in some countries.

[Parriss]

Thank you, I just looked at Kobo they don't have all same selection of books (but have the most popular titles), however online there is nothing but positive comments. I feel that this may be the time for change!!!

An additional question. You mentioned jailbreaking, the other person with this problem{who is alittle bit more willing to try something new } is wondering, if this jailbreak is done will the books just be able to be added to Calibre via 'add books to library' or would other steps be required.

Thank you for your assistance.

[Sirtel]

Originally Posted by Parriss

An additional question. You mentioned jailbreaking, the other person with this problem{who is alittle bit more willing to try something new } is wondering, if this jailbreak is done will the books just be able to be added to Calibre via 'add books to library' or would other steps be required.

The process is the same as with a non-jailbroken Kindle. However, you can downgrade the Kindle firmware to the previous version which still works with deDRM. Of course your Kindle will update again at some point (there may be a way to prevent this with a jailbroken Kindle, but I know nothing about it).

[Parriss]

Thank you so very much for the information.

I'll pass this on.

[JSWolf]

Originally Posted by Parriss

Thank you, I just looked at Kobo they don't have all same selection of books (but have the most popular titles), however online there is nothing but positive comments. I feel that this may be the time for change!!!

An additional question. You mentioned jailbreaking, the other person with this problem{who is alittle bit more willing to try something new } is wondering, if this jailbreak is done will the books just be able to be added to Calibre via 'add books to library' or would other steps be required.

Thank you for your assistance.

Before trying to jailbreak, make sure there is a method to block firmware updates with that Kindle and that jailbreak. If you cannot stop firmware updates, it's not worth bothering to jailbreak.

If you can block firmware updates, then you can jailbreak, and revert the firmware to an older version and block any updates.

[DNSB]

Originally Posted by JSWolf

If you can block firmware updates, then you can jailbreak, and revert the firmware to an older version and block any updates.

From some reports, some of the changes that Amazon has made with the newest firmware makes it impossible to revert to older firmware.