Looks like United is connecting to this program: https://www.tsa.gov/digital-id

The United App might be added to the list of Airline apps that can function as a digital ID.

I tried using my CO digital drivers license as an ID at DEN a few months ago and the TSA agent said that the Wifi connection was terrible, so the scanner didn't work well. I then tried more recently, but I didn't realize that I had to double click the side button on my iPhone, so it failed. Maybe the next time I will do it better.