The new PIN works great, good work.  Just two usability issues remain:

1. The "Receive" screen still defaults to USD (useless for me, since I want to see what I am sending in GBP).

2. As mentioned above, the back button tends to exit app completely rather than return to the previous screen.  So if I open airbitz now on my Android phone (still open in memory), it will open to the last screen I was looking at (let's say "Receive").  If I navigate to "Send" and then hit the back button, the app will close (rather than go back to "Receive" or home/directory). Maybe returning to the directory before closing the app is the answer.