A new detector exploiting the technology of Gas Electron Multipliers is under construction to replace the innermost drift chamber of BESIII experiment, since its efficiency is compromised owing the high luminosity of Beijing Electron Positron Collider. The new inner tracker with a cylindrical shape will deploy several new features. The analogue readout and two complementary algorithms to reconstruct the position will allow achieving a spatial resolution of 130 µm in a 1 T magnetic field. For this purpose, TIGER, a new custom 64-channel ASIC, providing time and charge measurements, has been developed. Here, a summary of the most recent results on detector and electronics prototypes is given.