This article reports on the upgrade of the reflectometry profile and fluctuation measurements in Alcator C-Mod. The reflectometer consists of five amplitude modulated O-mode millimeter-wave channels operating between 50 and 110 GHz. The system provides the electron density profile for densities up to 1.5×1020 m−3. An upgrade has been implemented to improve the reliability of the system, eliminate 2π ambiguities in the group delay measurement, and enhance the fluctuation measurements. An upgrade of the 88 GHz channel has been installed, which allows fluctuations on both the upper and lower sideband signals to be measured independently with high resolution. Some preliminary fluctuation and density profile results are discussed.