One of the major problems when moving from Drupal 5 to Drupal 6 was the slow rate of migration for many of the modules and themes that were contributed to the Drupal project by Drupal community members. If a site relied on a module that had not been updated, they had to delay upgrading their sites, assist in conversion efforts, find an alternative solution, or rebuild the existing functionality themselves. Thankfully, this should not reoccur with migrations from Drupal 6 to Drupal 7. A large number of module maintainers pledged to have full releases of their modules available the day that Drupal 7 is released. This list includes several key modules that are used by many sites.

We will look into some of the contributed modules that have Drupal 7 releases in Chapter 4, with information about changes you may need to make if you are using them in your Drupal 6 site.