MacRumors published a story that Apple has released the third beta of watchOS 10.4 to registered developers.
Apple Seeds Third Beta of watchOS 10.4 to Developers
Apple today seeded the third beta of an upcoming watchOS 10.4 update to developers for testing purposes, with the beta coming a week after the release of the second watchOS 10.4 beta.
To install the watchOS 10.4 update, developers need to open the Apple Watch app, go to the Software Update section under "General" in Settings, and toggle on the watchOS 10 Developer Beta. An Apple ID linked to a developer account is required.
