Thank you, apollon77,
let me understand the idea.
1. I specified a new command (ack=false) with some value by calling adapter.setState(,false).
2. I thought, the my adapter should process this command in a part of my code and then should confirm this change by calling adapter.setState(,true).
Instead of this, the ioBroker body (ie mqtt) confirms setting of state on its own. So, the state changing is not a command, but just a value.
OK. but how to understand a documentation sentence "States can be written as commands or as statuses…. "?
sorry for my stupid questions