MQTT Switch default state after power outage

Configuration
1

there is any way to set default switch state after power outage?

i use sonoffs to control my living room lights. (via mqtt)
i wonder if there is a way to auto turn them on after power outage.

thanks

2

if your MQTT server is protected (i.e. UPS), you can use the retain flag in the MQTT message so that the plugs can find back their previous state