MacRumors published a story that Apple has released the release candidate of watchOS 7.4 to registered developers.
Apple Seeds RC Version of watchOS 7.4 to Developers
Apple today seeded the RC version of an upcoming watchOS 7.4 update to developers for testing purposes, with the new beta coming two weeks release of the seventh beta and over two months after the launch of watchOS 7.3 with "Time to Walk" functionality, expanded ECG availability, and a new Unity watch face. To install the watchOS 7.4 beta, developers need to download the proper configuration profile from the Apple Developer Center. Once the profile is in place, the watchOS 7.4 beta can be downloaded through the dedicated Apple Watch app on the iPhone by going to General > Software Update.
