We saw a leak recently that showed off a new version of Google's Android Wear companion app, and now here it is. The design is certainly more in-line with Android 5.0 aesthetics, but it's not quite material. Also, you'll only get the new UI on Lollipop.
Left: Old, Right: New
So, there's not much to see here if you're on KitKat. The app will still have the black theme unless you're on Lollipop. The options are rearranged a little, and the settings are different. The screenshot feature that made an appearance in the leak isn't present, probably because it requires Wear 5.0. Oh well, the update is down below if you want it.
Update: As pointed out in the comments, this update also fixes media playback notifications on Lollipop. They didn't show up at all before. This makes me very happy.
The APK is signed by Google and upgrades your existing app. The cryptographic signature guarantees that the file is safe to install and was not tampered with in any way. Rather than wait for Google to push this download to your devices, which can take days, download and install it just like any other APK.
File name: com.google.android.wearable.app-220.127.116.110939-401580939-minAPI18.apk.
Version: 18.104.22.1680939 (401580939) (Android 4.3+).