"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
Everything New in watchOS 4.3: iPhone Music Controls, Portrait Orientation Nightstand Mode and More
We've outlined all of the changes you'll find in the watchOS 4.3 update in the video and the post below.
First and foremost, watchOS 4.3 once again allows Apple Watch owners to access their Apple Music Library for iPhone, a feature that was removed in watchOS 4.
With watchOS 4.3, there's a new "On iPhone" section in the Music app that lets you access your playlists, albums, songs, and artists. Prior to this update, you could access your music library, but only when playing music on the watch itself.
When playing music on the iPhone, you were only able to use the Now Playing feature to skip tracks -- there was no library access for choosing songs to play on the iPhone from the Apple Watch. Apple Watch owners have been complaining about the removal of iPhone music controls on Apple Watch since watchOS 4 debuted, so this should be a welcome change for many people.
Along with music controls, watchOS 4.3 adds your daily Activity information to the Siri watch face, so you can see your current progress at a glance without needing to open up the Activity app, and it introduces a new charging animation when the watch is placed on a charging puck.
The final new feature in watchOS 4.3 is Nightstand Mode while the Apple Watch is in portrait orientation. Since Nightstand Mode was first introduced, using it has required putting the Apple Watch in landscape orientation on its side. That's no longer necessary -- you can now use Nightstand mode in any orientation.
Apple doesn't make watchOS betas available to its public beta testers because there's no way to restore an Apple Watch to an older operating system, so the watchOS 4.3 update will be limited to developers until its public launch.
We'll likely see watchOS 4.3 in the spring alongside iOS 11.3, macOS 10.13.4, and tvOS 11.3.