This viewer was updated recently. Before that when I encountered a WP doc Id click on it and up would come a list of other apps on my iphone preceded by the notation: OPEN IN. The apps shown were those apps that have conversion capabilities such as File Converter, Good Reader, File App Pro, and the WP Viewer. Somehow the iPhone "knows" what selections may be useful. BUT...following the update i got a WP file, "Winmail.dat", and in trying to open this common WP file, the Viewer does not appear under the "Open In" menu. The WP viewer is no longer shown! So, until that gets fixed the Viewer is useless.