From Microsoft Game Studios:
This program includes several changes that should improve the smoothness of the simulation, especially during turns. There are improvements to the aircraft gauges, flight planner, weather simulator, and the aircraft's behavior. The Learjet 45 and the Boeing 737-400 ADF needles now correct for magnetic variation. In this update, the Autopilot-induced oscillations while following the ILS glideslope have been fixed. Other corrections include limiting the displayed ATIS frequencies to those tunable with the Communication radio.