If you ask Siri to get you an Uber, a feature that has been available since the launch of iOS 10, Siri will say that Uber hasn't activated that feature. In the "Siri & Search" section of the Uber options in the Settings app, there's also no longer a "Use with Siri" toggle.
Similarly, in Apple Maps, you can no longer select Uber as an option when choosing "Ride" when getting directions. This is also a feature that debuted in iOS 10.
Both Siri and Apple Maps integrations are still available for other ride sharing apps like Lyft, so the problem seems to be with the Uber app rather than with Apple's services.
The removal of both features was noticed by MacRumors readers and reddit users starting last week. It is not clear if Uber has deliberately removed these features or if it's a bug, and the company did not respond to a request for comment when contacted by MacRumors earlier this afternoon. We have also contacted Apple and will update this post when we hear back.
Uber integration with Siri, enabled through the SiriKit API, was a much touted feature when iOS 10 first launched, as was Apple Maps integration. Both Apple and Uber heavily promoted the two options when iOS 10 rolled out.