Apple today seeded the release candidate version of an upcoming watchOS 8.4 beta to developers for testing purposes, with the new software coming one week after the launch of the first betas and over a month after the release of watchOS 8.3.
To install watchOS 8.4, developers will need to download the configuration profile from the Apple Developer Center. Once installed, watchOS 8 can be downloaded through the dedicated Apple Watch app on the iPhone by going to General > Software update.