qwerty12 thank you very much for the info and the time to answer my questions. So far you are the only one doing so.

Actually I've found this link on how to use d-bus with python.

Just need to know what is the d-bus I should use for this matter.

If no-one knows how to do that, another idea I had is to clear the icon on any user action (tap, touch, button etc') - what is the d-bus for that?

And last idea was to clear the icon after the user closes the yellow "missed call" window manually. For that I need to check if the process for that window is alive - any idea how do I find out what is the process name for the yellow window?