The Apple Watch is getting a new software update that lets developers access Siri for certain functions in their apps. The watch is also getting a new Theater Mode, which means your watch doesn’t wake even when you raise your wrist. This is different from Do Not Disturb though. Your watch will light up only when you press it.
There were rumors about this feature in the past. Theater Mode with WatchOS 3.2 lets you mute the sound and keep the screen off but you will still get notifications.