The Kinect seems very low on Microsoft's priority list these days, and the new Xbox One S is a great indication of how much they don't care anymore. For those who happen to own Xbox One Kinect's and are upgrading to the Slim console (which is not a bad idea given how big the standard console is) you will not be able to use it right away. The new console will not support the Kinect out of the box as Microsoft has revealed, and requires an adapter in order to use the motion-tracking peripheral.
Xbox executive Matt Lapsen spoke to Xbox Wire about this subject sharing:
"In order to make the Xbox One S as compact as possible and make all of these updates, we removed the dedicated Kinect port from the back."
The good thing is Microsoft is at least willing to help with this problem, to use your Kinect you will need a dedicated Kinect adapter for USB Connection, and Microsoft will be giving these free to those who request them. At least the Kinect support is still there, otherwise it would not have been worth upgrading for the smaller system, even if Kinect is pretty pointless these days.