Rule for updating Tasmota version for sonoff switches

Just trying my first steps with sonoff switches.
Switching ON and OFF using MQTT messages is working, now I want to incooperate the maintance (firmware-update) as posted in here.

When running the rule as posted I get an error;

18:01:35.258 [ERROR] [untime.internal.engine.RuleEngineImpl] - Rule 'Sonoff Maintenance': The name 'publish' cannot be resolved to an item or type; line 21, column 17, length 57

It sounds like “publish” is not known, did I miss to read something in the link??

I think you need to install the mqtt action.

I knew that I missed something.