Google announced its fourth Developer Preview build of Android Wear 2.0 today, which arrives two and a half months after Developer Preview 3. At the time, the company delayed the release of the OS until early 2017.
In fact, the Android Wear Preview Program Overview still says that new builds should launch at six-week intervals. Milestone 4 is listed as having "near-final APIs and SDK, Play publishing"; after that will be a near-final system image, followed by the final release to OEMs.
Today's Preview promises "seamless authentication", implementing new APIs for OAuth and one-click Google sign-in. Tapping a button will allow users to authenticate from their phones, and with Google sign-in, they'll just have to select their account.
Another new feature is in-app billing. This will allow users to enter a four-digit PIN and purchase in-app content. There's also cross-device promotion, which will help users navigate to the Play Store to download an app; for example, if your Android Wear app works better if the phone app is installed, these APIs will help to make sure that the user has both.
There's also the return of a few features, including swipe-to-dismiss. Android Wear 1.0 apps are once again supported as well.
The Android Wear 2.0 Developer Preview is still only available for two devices: the Huawei Watch and LG Watch Urbane 2nd Edition. You can download the images here.
