Updating Headless Servers

[Kent Borg]

I am wondering how to best keep headless servers up to date with
security fixes, etc.

On my notebook I get notified when there is an update available.  Is
there a handy way to have a headless server e-mail me when updates are
available?

I know I could set up a cron job to do something like this, but I am
guessing there is probably already a feature like this that I simply
need to configure and turn on.  Is there?

Thanks,

-kb