oggers:
ITT will rise due to the reduced mass flow rate of air going to the combustion chamber as you climb.
Well, this may or may not be true for a given engine type, depending on the characteristics of the control system (whether governing to a constant core speed, constant corrected speed, constant torque, constant CDP, etc etc.)
If an electronic control, it's all done with ones and zeroes; if hydromechanical, then it's bellows and cams and flyweights.