Apple today began rolling out the fifth beta build of watchOS 4.3.1 for testing on the Apple Watch before an initial release to the public in the near future. This comes a week after the fourth build was released. To install the beta, navigate to the Watch app on your paired iPhone and tap the “My Watch” tab. From there, go to General > Software Update and you should see the build ready for download. Be sure to place your iPhone on Wi-Fi while downloading this software as it’ll surely gobble up plenty of your data.
So far, it looks like watchOS 4.3.1 will mainly contain bug fixes and security patches. Of course, we’ll let you know of any new user-facing changes made.