"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Seeds First macOS Sierra 10.12.4 Beta With New Night Shift Mode to Developers
The first macOS Sierra 10.12.4 beta is available for download through the Apple Developer Center or the software update mechanism in the Mac App Store. A public beta will likely be available for public beta testers later this week.
We don't yet know exactly what features, bug fixes, or changes will be introduced in the macOS Sierra 10.12.4 beta, but because it accompanies iOS 10.3, it could be a more significant update that focuses on changes beyond bug fixes. According to Apple, the update includes a new Night Shift mode that automatically shifts the display color to the warmer end of the spectrum after night, offering Mac users an alternative to F.lux. Night Shift has been available on iOS devices since iOS 9.3.
macOS Sierra 10.12.4 also includes Shanghainese dictation support for converting text to speech, and Siri will soon gain the ability to display cricket scores.