There are not so many players that come with support for AAX files to let you listen to your favorite audiobooks on any device.
Moreover, it is likely you interacted with Audible’s proprietary file format, AAX, especially if you meant on enjoying your audiobooks outside the app. If you are one of those people who prefers listening to reading books, then probably you heard about or even used Audible, which is one of the top audiobook providers.
Bugfix for 1.17: Mid-level folder for series title was created despite option off (#76).What's new in AAX Audio Converter 1.17.1:
