Updating your modules to use the new configuration objects instead of variables is really easy and makes your code much more readable and flexible. After reading this chapter, you should now be able to differentiate between persistent configuration (deployable) using the Configuration API and environment-specific data using the State API.

Upgrading a Drupal 6 site to Drupal 7 seems easier at first glance since you simply have to run update.php after preparing the site and updating the code base. However, as soon as you have installed some contrib modules, it gets complicated. The modules need to convert their data to the correct structure, and sometimes, you need to write your own update hooks. Using Migrate as the base tool for major version upgrades is much more flexible and robust.

In the next chapter, we will show you how to deal with configuration on multilingual sites and how you can provide translations for configuration.