The latest beta build for WhatsApp now has full support for Android Wear devices baked in. While you can see notifications from any app using Android Wear, WhatsApp has given their app the full treatment. The beta build includes stacked notifications, a preview of the entire message, and the ability to respond via voice.
Today's release hasn't yet made it's way to the official beta channel, but it is already available from WhatsApp's servers. You can download it here if you don't want to wait.
Via: 9to5 Google