re: How can I update the plugin without losing information?
Normally you would just click the “update now” link that WordPress creates. You should be able to safely deactivate and delete Connections and then reinstalled from the Add New plugins WordPress admin page. I say should because I wonder if the files were modified and that is why you are not seeing the WordPress update notification.
I suggest making sure you backup before updating to ensure you can undo the update incase the version you have installed was modified and no longer compatible.