There is a big problem in IWO 2/IWO 2A(IWO 3), these two smart watch has the interface hided in the band slot, it is not easy to update the firmware when there is some problem within the smart watch, now the IWO 3 plus changes to the pins connection instead of wireless charger, that give space to install a better heart rate monitor sensor, and make it possible to maintain the smart watch with a firmware update, even the watch is dead, it can be recoverd again by reflash the firmware if no hardware damage.
this video shows how to update the firmware of IWO 3 plus