There isn't much to say about updates. EuHunter uses Microsofts ClickOnce Deployment to provide you with an actual version. EuHunter checks for new Updates after each start and tells you about updates if one is found.
You can search for updates manually by clicking Tools -> Check for update in the main window's menu.
ClickOnce gives you the option to step back to the last version via the windows software control panel.