From 01 to 03 March 2023, the final conference of the BMBF-funded joint research project "Urban Climate in Transition" [UC]2 took place in Berlin. The 3DO+M module also met and presented the results of the different validation studies of PALM-4U. Among others, we presented our results on particle flux measurements in Berlin (e.g. Straaten and Weber, 2021, ACP) and on energy balance measurements on an extensive green roof (Konopka et al., 2021, JGR Biogeossciences). With PALM-4U, an excellent microscale model is now available for the investigation of urban climatic issues, which will certainly be used in many studies in the future.