The MEG II collaboration presents today, April 23, 2025, during a seminar at the Paul Scherrer Institut in Switzerland, a new result in the search for the decay of a positive muon into a positron and a photon. If observed, this decay would be a clear sign of physics beyond the Standard Model of particle physics. No significant excess of events over the expected background has been revealed, and a new upper limit has been set on the probability of this process — currently the most stringent limit in the world. The results are described in a paper https://arxiv.org/abs/2504.15711 submitted to the journal Physical Review Letters. MEG II will continue taking data until 2026. The MEG II collaboration includes about 70 physicists from international research institutions. A joint INFN Roma and Sapienza group (G. Cavoto, E. Gabbrielli, D. Pasciuto, V. Pettinacci, F. Renga, S. Scarpellini, C. Voena) is part of this collaboration and played a key role in the measurement.