yep now it works but still a bit weird óO
after reading your reply - in the browser-window of the itch-desktop-app - hit the big red update button and all it did was opening the itch.io-game page as a new tab in my google chrome browser
had to go back in the game library - right click on it and check there for updates to download it
this app seems to still be a bit weird - thats one of the reasosn I'm still hesitating to see how it works in tandem with patreon and co...