This paper presents the technical improvements and experimental characterisation of a hybrid superconducting 18\,GHz Electron Cyclotron Resonance Ion Source (ECRIS) manufactured by Pantechnik. Since the last one manufactured in 2011, the source has undergone significant upgrades to enhance its performance and reliability for heavy ion beam production. Key improvements include optimisation of the magnetic confinement system, aiming to increase the production of highly charged ions while maintaining stable operation at high RF power levels. An extensive experimental campaign is currently underway at Pantechnik's facilities to characterise the source performance on a selection of ions (N, Al, Ar, Au, Pb) and the goal of demonstrating stable Xe$^{28+}$ and Ta$^{36+}$ beams.