Before upgrading core, you should do two things:
Once you have completed these steps, you are ready to proceed with your upgrade.
When performing a core upgrade, we will replace the old version of Drupal core with the updated version. This process involves five steps:
Log into the new site as UID1; place the site in maintenance mode, and run
update.php
.Download the new codebase from http://drupal.org/project/drupal.
Extract the Drupal codebase.
Delete the
sites
directory from the freshly downloaded codebase; replace it with thesites
directory from your existing site.Replace the existing codebase with the new codebase.