In order to complete the exploitation of the JET ITER-like Wall and to take full benefit from deuterium-Tritium experiments on JET, a set of diagnostic system refurbishments or upgrades is in progress. These diagnostic enhancements focus mainly on neutron, gamma, fast ions, instabilities and operations support. This effort intends to provide better spatial, temporal and energy resolution while increasing measurement coverage. But also previously non existing capabilities, such as Doppler Reflectometry, will now be made available for scientific exploitation. Guaranteeing diagnostic reliability and consistency during the expected DT conditions is also a critical condition for the work and systems being implemented. An overview of status and scope of the ongoing projects is presented.