Google-maps/">Google Maps version 26.44.4 is being reported to add full support for the iPhone Duo’s two displays. Google’s App Store notes describe the update only as including bug fixes.
Previously, the app appeared slightly offset on the outer screen to accommodate the iOS dock. On the inner display, it used the standard iPhone layout, which could be positioned on either side but left much of the screen unused.
With the update, Google Maps fills both displays. The main change is on the inner screen, where the search box and menus sit on the left and the map or satellite view spans the remaining width, in a layout similar to the app on iPad.
Street View also uses the wider display: it appears on the left, with the map on the right. The two sections cannot apparently be swapped, but Street View can be expanded to fill the screen. Closing the iPhone Duo while Street View is open moves it to the outer display, where a close button returns to the map.
Sources: GSMArena.