Kindle v1.26: Your Kindle app requires an update to view this content

this is no longer working

https://github.com/apprenticeharper/DeDRM_tools/wiki/Exactly-how-to-remove-DRM

If you want to use the KFX format, you must use Kindle v1.26 or earlier

Kindle v1.26 fails to download new books with

Your Kindle app requires an update to view this content

see also

https://www.google.com/search?q=%22your+kindle+app+requires+an+update+to+view+this+content%22+site%3Amobileread.com

https://www.mobileread.com/forums/showthread.php?t=361503&page=57

anything published as of today 4/23/25 you will get the error "Item not available for this device type. Your Kindle app requires an update to view this content."

https://www.mobileread.com/forums/showthread.php?t=351734

I gather you have missed all the posts about issues with Amazon changing how their ebooks are delivered on 2023-Jan-03.

For more information, check the Amazon forum, see Amazon and DRM changes, in the calibre forum, check the stickied Dealing with Kindle for PC/Mac 1.19 and KFX in calibre.

workaround

1. revert the amazon order and get a refund
2. buy the book from kobo.com
3. download EPUB with kobo-book-downloader

kobodl user add
kobodl book list
kobodl book get xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx