How to get e-mail from Drupal.org about new Drupal releases?
Go to https://www.drupal.org/user , click on the "Edit" tab and from there, the "My newsletters" tab. This will allow you to subscribe to "Drupal newsletter" and "Security announcements".

Also to get notifications of Drupal core or module updates for a particular Drupal site that you run, go to Reports -> Available updates -> settings (/admin/reports/updates/settings) and enter your email address and the desired frequency (daily / weekly) and type (security / all) of updates.