Upgrade Drupal

Deprecated code is any code flagged for future removal, but which has not yet been removed to ensure that existing code which relies on the to-be-removed code will continue to work. When an API, or feature, becomes deprecated it's a warning to all developers that at some point in the future this thing they are relying on will not exist, and they'll need to update their custom code to a new approach. Preferably before the existing one gets removed.

In this tutorial well:

• Learn about why, and when, code is deprecated in Drupal
• How to identify custom code that is using deprecated features
• How to determine an appropriate upgrade path to the new API

By the end of this tutorial you should be able to explain what code deprecation is, and why it's important for Drupal's continue innovation, as well as how to update your own code when an API you rely on becomes deprecated.

There’s no one-size-fits-all path to upgrade from Drupal 9 to Drupal 10, but there is a set of common tasks that everyone will need to complete.

In this tutorial we’ll:

• Explain the differences between Drupal 9 and Drupal 10 that affect the upgrade path.
• Walk through the high-level steps required to upgrade from Drupal 9 to Drupal 10.
• Provide resources to help you create an upgrade checklist and start checking items off the list.

By the end of this tutorial you should be able to explain the major differences between Drupal 9 and 10, audit your existing Drupal 9 projects for Drupal 10 readiness, estimate the level of effort involved, and start the process of upgrading.

There’s no one-size-fits-all path to upgrade from Drupal 8 to Drupal 9, but there is a set of common tasks that everyone will need to complete.

In this tutorial we’ll:

• Explain the differences between Drupal 8 and Drupal 9 that affect the upgrade path.
• Walk through the high-level steps required to upgrade from Drupal 8 to Drupal 9.
• Provide resources to help you create an upgrade checklist and start checking items off the list.

By the end of this tutorial you should be able to explain the major differences between Drupal 8 and 9, audit your existing Drupal 8 projects for Drupal 9 readiness, estimate the level of effort involved, and start the process of upgrading.

Drupal 8.8.0 introduced a bunch of new features intended to make it easier over the long-term to maintain a Drupal project using Composer. In doing so it establishes some new best practices, and moves into Drupal core solutions that were previously maintained by the community. This is all good news. But, it means if you're using Composer to update from Drupal 8.7.x or lower to 8.8.0 or higher you'll need to do a bit of additional work to untangle everything.

This tutorial is especially useful if you started your Drupal project using the drupal-composer/drupal-project template and would like to convert to use the new templates (i.e. drupal/recommended-project or drupal/legacy-project) included with Drupal 8.8.x core.

In this tutorial we'll:

• Convert our project to use the new drupal/core-recommended, and drupal/core-dev Composer packages
• Explain which commonly used Composer packages are deprecated, and which new ones replace them
• Learn how to use the drupal/core-composer-scaffold Composer plugin
• Cover tips for troubleshooting updates

Furthermore, in order to Upgrade to Drupal 9 from Drupal 8, you will first need to update your Drupal 8 site to at least version 8.8, as the upgrade paths for Drupal 8 site from before Drupal 8.8.0 have been removed from Drupal 9.

By the end of this tutorial you should be able to update your Drupal projects using Drupal core 8.7.x or lower to Drupal core 8.8.0 or higher using Composer. And be ready for an upgrade to Drupal 9.

As new major versions of Drupal are released, contributed modules need to be updated for compatibility. As of right now (October 2021) there are a lot of contributed modules with a Drupal 8 release and a patch in the queue to make them work with Drupal 9. However, there's no official Drupal 9 compatible release for the module, so the module can't be installed with Composer. This creates a circular problem where you can't composer require the module if you don't patch it, but you can't patch it until after it's been downloaded by Composer.

To help solve this common issue, Drupal.org provides a lenient Composer endpoint that publishes all modules as compatible with Drupal 9 regardless of whether that's true or not. By using it, you can composer require the module and then use cweagans/composer-patches to apply any necessary patches.

In this tutorial we'll:

• Add the lenient Composer endpoint to our project's composer.json file
• composer require a non-Drupal 9 compatible module
• Use Composer to download and apply a patch that makes the module Drupal 9 compatible

By the end of this tutorial you should be able to use contributed modules that require a patch to be compatible with Drupal 9.