I uninstalled version 2 and installed version 3. Still don't have any updates. But, I'm seeing something I missed before. After running the first time, I change settings to enable pop-up notifications and set update interval to 1 day. Then I exit and start the app from the menu again. Notification says "The next scheduled check for updates is DISABLED" (in CAPS).
When I look in ~/.update-notifier-launcher/SETTINGS at the days file, the value is set to 1. Judging by the pop-up message, it must be coming from the Read Next Update Time (NUT) settings section.