The performance of Electromagnetic Calorimeter is important for physics studies involving neutrals and electrons. To cope with the large luminosity to be operated at during high-luminosity LHC and sustain radiation doses up to 1 MGy, a major upgrade of ECAL is needed. A baseline strategy is proposed to combine the existing Shashlik technology in outer region with a so-called Spaghetti Calorimeter (SPACAL) technology in the central region. The latest performance measurements of the SPACAL and Shashlik prototypes with testbeam and simulation studies of the Upgrade ECAL setup will be presented in the talk.