Hey Michele,
>> "- I see the update window, it will be best if no window is displayed (add the cmd switch /hideui)"
You can do that by updating via a Windows Service: https://wyday.com/wybuild/help/faq.php#silent
>> "- I have to close programmatically my program before launch the wyupdate command otherwise the updater ask me to close the program. Why this can't be made automatically? If you find the exe running close it! (add the cmd switch /killapp)"
Because wyUpdate is not destructive. It requires you make the decision of whether you want to kill your app (and all the necessary "shutdown" operations that you need to complete).