This plugin will give you three alternatives for managing your WordPress updates:

• Update automatically – This updates WordPress/themes/plugins automatically and sends an email to the site admin when an update has been performed.
• Update automatically (no email) – Same as the first alternative, but without the email.
• Inform about updates once a week – This will send an email to the admin once a week if there are anything that can be updated.

Notice that only plugins/themes that resides in the WordPress
repository will be updated/informed about.

The plugin has not been tested and is not primarily made for multi site-installations.