The fourth beta of watchOS 3.1.1 has now been seeded to developers. We find this update two weeks after the third release. Right now we’re unsure what’s new with this version. Since it is a smaller update, it likely brings some bug fixes and improvements.
To get this update developers can go to the Watch app and download it from there. If you don’t have watchOS 3.1.1 yet you can go to the developer center and get the profile from there.