You need to separate two words: update and upgrade, they mean two different actions.
- Updating refers to bring your site up to a latest Drupal minor release, for example, from Drupal 7.2 to Drupal 7.8.
- Upgrading, however, is a complex task of moving your site from one major Drupal release to another, such as from Drupal 6 to Drupal 7.
In this section, I only show you how to update your Drupal site. Upgrading is a complicated job which you need helps from professional Drupal developers.
There are basically two situations when you need to upgrade your sites:
- Update modules: a Drupal site may have many contributed modules. When those modules have new versions, you should upgrade them. But you do not have to upgrade a module right after its new version is released. I do module upgrading once per month for this Symphony site.
- Update Drupal core: when a new Drupal core is released, it is necessary to upgrade because the new core may contain security fixes.
Go to Admin > Reports to check the update avaiable.
Now let's move on.