Sorry, I don't know of any that do that directly. KOReader can sync with Calibre on the desktop, so you could perhaps set that up as a passthrough. Or you coul

Sorry, I don't know of any that do that directly. KOReader can sync with Calibre on the desktop, so you could perhaps set that up as a passthrough. Or you could use something like BookDrop [1] or IFTTT that sends ebooks from Dropbox to the Kindle over Amazon's WhisperSync service. Those are stored in the "documents" folder on the Kindle, where KOReader could read them as well as the stock reader app. [1] https://getbookdrop.com/ https://getbookdrop.com/