But good Reder in the local version 2.10.x not Android 4.4 KitKat or upgedatete (Kindle) Fire HDX with FireOS 4.x compatible. The Google Play store OpenDocument Reader but since November 2013 compliant as KitKat version 2.17.x available. So does Amazon or the developer the necessary update upload slept for a whole year, and now customers have the salad. (This is not the only app with the problem, nevertheless HDX customers prematurely forcibly upgraded to FireOS 4.x, which then many popular apps for lack Update in Amazon Appstore no longer work properly.)
At this stage, without 2.17.x update I would recommend anyone to buy the app! Unless you have a device for which there will be no eh Android 4.4 or later update (old Fire HDs for example).