The operating system of the CASIO fx-9860G AU can be up-dated. If updated to OS version 2.0 or later then it will have much of the functionality of the 9860G AU PLUS. However, it will not have the natural input in Graph and Equation modes which is a feature of the PLUS model. It will also still differ from a PLUS model in terms of memory size and screen illumination.
To update the operating system visit the CASIO Worldwide Education Website at https://edu.casio.com/dl/ and follow the links.
Note: the update software is different for the 9860G AU and the 9860G AU PLUS models. Ensure that you use the correct update software for your model.