'Check for updates in a new thread, if enabled.'

def check_for_updates(self):

    system = common.get_platform()
    if ((system == 'Windows') or (system == 'Darwin')):
        if self.settings.get('use_autoupdate'):
            def update_available(update_url, installed_version, latest_version):
                Alert(strings._('update_available', True).format(update_url, installed_version, latest_version))
            self.update_thread = UpdateThread(self.onion, self.config)
            self.update_thread.update_available.connect(update_available)
            self.update_thread.start()
