Takeaway 3 The old Kindle app cannot download Kindle books published since January 3, 2023, and you need to update the Kindle app to version 1.39 or later to download these books.
In this case, if you have a Kindle device registered with your Amazon account, you can download Kindle books via "Download and transfer via USB." Here are the detailed instructions for removing DRM from Kindle books published after January 3, 2023.
If you don't have a kindle device, but still need to remove kindle drm published after 2023, then you should use Epubor Kindle Converter.