Mqtt problem

Alright, so there is no topic being listened to at all in your v1 config.
You can remove the stateTopic part of your channel config.

Your v1 config is converting openHAB ON and OFF commands into “1” and “0” messages.
You’d need to do that in your channel as well. The binding provides a simple tool for that, its in the documentation.
You can add on=1 and off=0 parameters to your channel.

like this

Type switch : Varme_VaerkstedChannel “Switch_varme_vaerksted” [commandTopic="/Sonoffth1/gpio/12, on=“1” , off=“0” "

Now is running I removed the “”