It does, and it's no longer beta now as well, though that didn't really didn't seem to matter. From the home page click on the three bar menu icon in the top left and then scroll down to Track my Bags. It's been working pretty well lately, and on a couple recent trips between IAH and LAX when my bags were loaded onto earlier flights when I checked upon landing it would tell me that they were then already available for pick-up at the UA baggage desks.