The LIGO-Virgo-KAGRA collaboration entered the second part of the O4 run on the 11/04/2024. In this presentation I will talk about the work of the Virgo calibration team during the preparation for the start of O4b. From the Photon Calibrator power calibration to the Virgo Actuators calibration I will describe the different steps allowing to reconstruct the GW strain data from the interferometer dark fringe signal as well as to monitor this reconstruction. I will finish by discussing briefly a new project on ET mock data challenge with MBTA
