I just tried it out: the old email address was notified.
This is an automated message to let you know that your email address for
%{site_name} has been changed. If this was done in error, please contact
a site administrator.Your email address has been changed to:
%{new_email}
You can check the email logs at /admin/email-logs. If you filter by username, you should see both the confirmation email sent to the new address and the notification sent to the old address.
