Hi @monsieurpablo ,
I changed the default assumptions input to the SolarCal model in the new LBT plugin and this might account for some of the differences. In Legacy, the human subject was always facing South by default but, in LBT, we have the human subject rotate such that their back is always partly to the sun (at a 45 degree angle to it). This new default assumption seemed more realistic since people usually don’t like to look directly into the sun.
Looking at your file, the MRT values out of the Legacy and LBT components are pretty close to each other:
The big difference in the UTCI values from the file that you uploaded comes from the fact that you connected wind speeds to the LBT UTCI component but you did not do the same for the Legacy UTCI component.