This document outlines the steps and important considerations for upgrading a Drupal site from version 5 to version 6. It recommends backing up the site files and database, installing a clean Drupal 6 site for testing, preparing the D5 site by disabling modules and changing themes, and exporting the database before running the update.php script. It warns that running update.php without being logged in as the user 1 account and updating theme .info files are common "gotchas" to watch out for during the upgrade process. Links are also provided for more advanced upgrade approaches and guides on converting Drupal 5 themes and modules to version 6.

1. Drupal Gotchas in a D5 to D6 Upgrade