The sixth beta of watchOS 3 was just now seeded to developers. We find this only one week and one day after the fifth release. This beta brings bug fixes and stability improvements. Other than that there is nothing major. We should be seeing the GM update coming in a few weeks, as it’s expected to launch mid September.
To get the latest update users can go to the Watch app and get it from there. Or you can download the profile from the developer center.