We describe the upgraded Magnetic Proton Recoil fusion neutron spectrometer (MPRu). The origi-nal MPR was installed at the JET fusion experiment in 1996, and was designed for diagnosis of the 14-MeV neutron emission in high-power deuterium-tritium (DT) fusion experiments. The goal of the MPR upgrade project is to widen the operational range of the instrument to the full range of fusion relevant neutron energies, 1.5 < E n < 18 MeV, to increase its flexibility and to improve the background immunity of the spectrometer's focal plane detector. In this paper we describe how these goals have been achieved by the installation of a new detector hodoscope, based on phoswich scintillators, in combination with state-of-the-art digital data acquisition electronics and enhanced monitoring capabilities. Examples of test results and predicted performance are given.