We lucked out in July. Sis couldn't get the app to work either, but since we fly as friends and family, they comped us.My latest saga - they won't even take my credit card when I hand it to them!
Flew to Denver this past week on United. I always buy a drink or 2 when flying. Get on the plane only to realize they no longer take cash or CREDIT CARD while onboard. You must save a credit card to your rewards account or on the United app. I had already tried to download my boarding pass on the app and knew that I didn't have the latest update and couldn't get it because my phone is too old. It said it could download the latest and greatest app for my version of phone but it was never able to load.