Comment 19 for bug 1817559

Changing the setting for how often to automatically check for updates to 'Never' instructs the system not to automatically run 'apt-get update' to check for updates. It does not invalidate the results of a previous 'apt-get update' run which has already found that there are updates waiting to be applied.

If there are already security updates waiting to be applied, the behavior when "Automatically check for updates" is set to "Never" is effectively undefined. This is the "When there are security updates: <blank>" - the option is greyed out but in practice what this actually means is that the behavior is the same as "Display immediately".

I am inclined to argue that this is a bug in software-properties, which should *show* that any available security updates will still result in a prompt, not a bug in update-notifier for doing the prompting. The difference between the two, after all, is a one-time pop-up that is easily resolved by applying the security updates.

Making it easier to ignore security updates than it already is would be an antifeature.