Secure site is mandatory not an option. Keeping your Drupal web site up-to-date is the best way to secure it. Periodically, Drupal.org will release a new upgrade, most of the time, it is a security update. Once a new release is announced, you need to upgrade immediately to avoid some serious trouble.

Upgrading a Drupal website is simple, but you need to backup everything, specially your database, before going with any upgrade. There is one very important thing I want you to note in upgrading your Drupal website.