I’ve done that and I still see 2.15 for almost all of my switches (except 1 that is on 2.18 and Z2M correctly shows that, and 1 that is on 2.14 that I can’t get to update even to 2.15).
I have some 2.15 switches that don’t show that they need an update, while some show the button to upgrade.
I’m on Z2M 1.38.0-1 and HA 2024.5.4