and going by what Microsoft has posted for the spring creators update it will still use the toggle method so on or off, there is a calibration tool added that is beta but doesn't sound like it will work for Kodi
HDR Video on more Windows PCs: Many newer devices are
capable of HDR video, but needed to be calibrated in the factory to enable HDR. Now, we are expanding HDR video access to more users via new functionality via Settings > Apps > Video playback. If the “Stream HDR video” toggle can be switched to “On”, your device can be calibrated for HDR video.To try our experimental calibration tool, click the link “Change calibration settings for HDR video on my built-in display”. This allows you to change the way HDR video appears on your device, allowing you to find your preferred balance between details in dark scenes and details in bright scenes. This tool is still early stage, and we’d love any feedback you might have as we are getting this tool ready for release with RS4.