It is supported by the sensor, but not in the camera's software yet. As far as I know, it will be in a future software version.
Once it is supported, cameras with monochrome sensors will be able to turn binning on or off in software.
To use 2x2 binning on a color sensor, the LUX330 would be needed; it can't just be changed in software because of the larger pixel size on the color filter.