Generally speaking, the switch stays OFF after recovering from the electricity cut-off, which can be inconvenient for smart home switches. The power on state feature allows you to decide the status of the switch. Sonoff products that support power on state: Sonoff Basic, Sonoff RF, and Sonoff S20.
*Please note that those devices shared by others don’t be allowed to set the power on state.
You can set the default power on state for the device to be automatically in ON, OFF or KEEP status. KEEP means your device will be in the same state as it is before electricity cut off. Please go to Setting to change the default power on state, which is OFF.