The main progresses achieved since the publication of the accelerator roadmap in 2021 were focused on Nb material structure (medium grain – MG – and large grain – LG), heat treatment with or without gas (N2 doping, N2 infusion,…), surface polishing and field emission reduction ; the first 3D-printed cavities by additive manufacturing (AM) aiming at lowering both cavity production cost and environmental footprint (through enhanced cooling efficiency) have been produced both at 1.3 and 3.9 GHz. Nb bulk fine grain (FG) material remains the best candidate to achieve the high performances needed for the future HEP machine, still with margin for improvement. To reduce manufacturing costs, LG and MG are studied, also considering compliance with vessel pressure code needed for cold operation. Cavity manufacturing via AM or spinning is being carried out and investigations on LG cavities are ongoing. Experience in heat treatments and surface treatments is still pursued.
