I was using the free version of TripIt prior to the annoucement about the app.
After 12/1 I downloaded the AMEX app, and logged in using my AMEX account, and then logged into my TripIt existing account via the AMEX app.
The good news is that it automagically upgraded my TripIt account to Pro at no cost. The bad news is that the OAUTH function needed to allow the AMEX app to access my TripIt data. I logged a support ticket with TripIt who replied that I should contact AMEX.
I reinstalled the TripIt app, and it works fine. Not sure what I'm missing by not using the release 1.0 version of the AMEX app, other than some low contrast grey screens.