Calibre is an open-source e-book library management application that enables you to manage your e-book collection, convert e-books between different formats, synchronize with popular e-book reader devices, and read your e-books with the included viewer.
Download: Portable | Windows 64-bit
View: Calibre Home Page
https://download.calibre-ebook.com/4.23.0/
https://github.com/apprenticeharper/DeDRM_tools/releases/tag/v6.7.0
https://github.com/apprenticeharper/DeDRM_tools/releases/download/v7.2.1/DeDRM_tools_7.2.1.zip (works with calibre 6.6.1)