From time to time, there will be minor updates to Drupal core. If the release is designated as a security update, you should apply the update as soon as you can. Otherwise, you may choose to apply the update at any time to receive the bug fixes it contains. There are also major release upgrades; these you may want to apply so you have all the new and powerful features.
Whether or not you apply a major release upgrade is highly individual to the person responsible for that decision. Upgrading to a new major version usually requires a significant investment of time and work, as a lot may have changed between versions. If everything is working great for you, and you don't want to add any of the new features, you may decide to stick with your current major release of Drupal.
About Drupal versions
What's the difference? Major versions (upgrade) versus Minor versions (update)
Before you start updating or upgrading your Drupal installation it is important that you know the difference between a major and a minor version release.
- A major version of Drupal core is represented by the number before the first decimal. For example Drupal 5.1, Drupal 6.1, and Drupal 7.1 are all different major releases. This is considered an upgrade.
- A minor version of Drupal core is represented by the decimal. For example, Drupal 6.1, 6.13, and 6.23 are all different minor releases of Drupal 6. This is considered an update.
You can read more about Drupal's version numbering in our Documentation.
Major releases include changes to core and how Drupal functions. New tools, structure changes, how everything works and looks, can be changed in a major version update.
Minor update procedure
With a minor release update; such as from Drupal 7.1 to the latest Drupal 7.x version, you do not have to apply all the updates that have been released between the versions. You can jump directly from 7.1 to that version. See Update Drupal Core.
Major upgrade procedure
A major release upgrade requires you to first update to the current minor release prior to applying the major release update. If 6.19 is the current version of Drupal 6, and your site is running 6.13, you would first need to update to 6.19 and then apply the update to the current major version 7.
You cannot skip major releases when upgrading your site. This means that if you want to upgrade a Drupal 5 installation to Drupal 7, you must first upgrade from Drupal 5 to 6, and then up to Drupal 7.
When performing a major core update on a complex site (ie. from D6 to D7 or D7 to D8), best practice dictates that you replicate all possible configuration (such as modules and settings) on the new site, then use the Migrate API to migrate data. This is especially true when upgrading from D7 to D8, where the database update system (update.php) can no longer be used.
It may also be useful to review the Comparison of Content and User Import and Export Modules.
Contributing upgraded versions of contrib modules
Maintainers of projects on drupal.org can get assistance from the change records impacting module developers, d8cx.org, and videos from Drupalcons and camps showing upgrading an example pants project.
Upgrading custom modules on your site
Upgrading your custom modules will involve similar tasks as maintainers of contrib modules go through. So that documentation might be helpful. Some changes will only affect your modules, for example module name length requirements.
Keep up to date on security announcements
It is strongly recommended that you always keep your Drupal site up to date with the very latest minor release available, to remove known security vulnerabilities and existing bugs.
Following are some of the most common ways to stay informed:
- Your website: Via the Update manager (Drupal 7) and Update status (Drupal 6). Drupal can check for the latest release of core and any installed modules and themes. For more details visit the Update manager (and Update status) page.
- Security Announcements:
- Security advisories page: All security announcements are published to this page
- Security newsletter. Log in, go to your user profile page and subscribe to the security newsletter on the Edit > My newsletters tab.
- Security advisories feed: You can subscribe to the RSS feed of the Security advisories page.
More information about upgrades
- Read UPGRADE.txt located in Drupal's root directory.
- Read the release announcements for the version to which you're upgrading.
- Upgrading to the most recent version of a contributed module, see How to update a module.
- Find your contributed module Upgrade Status via this module!
- Use Drush to easily do minor updates from the command line, and the Drush Site Upgrade script to walk through a major upgrade.
- If you are the maintainer of contributed or custom: