Drupal sites require periodic upgrades. These upgrades should be considered part of the maintenance process, and Drupal includes a core module—Update status—that simplifies this process. The Update status module provides an overview of the modules installed on your site, and informs you if they are out of date.
Tip
Make sure that the Update status module is enabled by clicking the Administer | Site building | Modules link, or by navigating to admin/build/modules.
The Update status module informs you of two main types of upgrades:
maintenance
security
A security upgrade patches a security hole, and requires an immediate upgrade. A maintenance release adds functionality, or fixes non-critical bugs. Whenever there is a new core Drupal release, you should upgrade your site to the new release. For contributed modules, maintenance releases should eventually be included, but, unlike security releases, they are not an immediate priority.
The updates page is available at Administer...