Apple today has seeded its first beta of macOS 10.12.4 beta to developers alongside iOS 10.3 beta 1, and tvOS 10.2 beta today. This comes several days after the public release of macOS 10.12.3. The new beta includes native Night Shift support on macOS, among other things.
Night Shift can be found under System Preferences > Displays > Night Shift.
macOS 10.12.4 beta 1 is now available for download via Apple’s Developer Center. The beta is currently for developers only but we expect it to come out to public beta testers in the next few days.
It is highly unrecommended to run this beta on your daily driver. However, if you find anything new let us know in the comments below!