It is a maintenance and security release of the D7 series. This release fixes security vulnerabilities and all sites owners are urged to upgrade immediately.
There are no changes have been made to the following files: .htaccess, web.config, robots.txt and default settings.php. That means there are no need to upgrade these files custom versions. But running update.php is required for this update in order to ensure a site cache clear. (There are no changes to database schemata.)
Drupal allows several way to upgrade its core. If you are not sure which one to choose, visit project's update page to read about each of them to find the right one for your project. Remember, before making any changes create Drupal's data base backup, even better full system back up. If you need any assistance with your Drupal based website, contact Web Admin. We back up your files and update your website to the latest version.