calibre is a powerful and easy to use e-book manager. Users say it’s outstanding and a must-have. It’ll allow you to do nearly everything and it takes things a step beyond normal e-book software. It’s also completely free and open source and great for both casual users and computer experts.
Version 8.0.1
And it allows plugins… there is a really good one on GitHub for “fixing” books you paid for that don’t work with your preferred e-reader.
I don’t mind the idea of DRM but the fact that it always locks you into the very worst apps is insufferable.