Tips on Upgrading to Drupal 10

Nevin Katz
11 min readMar 2, 2024
Photo by Rubaitul Azad on Unsplash

If you work on Drupal websites, you likely are no stranger to the version end-of-life dates and the quick pace of new releases. After Drupal 8 lost support in 2021, Drupal 9 also reached EOL in November 2023, so we recently migrated several of our websites to Drupal 10.

While the specifics of a D10 upgrade vary from site to site, they all entail common under-the-hood changes. One such change is the upgrade to Symfony, the underlying PHP framework for many of Drupal’s core components. For most of our sites, we upgraded or patched community-supported modules, made syntax changes to custom code, and either removed or replaced modules that were incompatible with Drupal 10.

To achieve these changes, we set up an upgrade process that handled five main areas:

  • Community-Supported Modules
  • Drupal Core
  • Vendor packages
  • Database updates
  • Custom Code

Below is a quick rundown of the upgrade process we developed to handle the above areas.

Charting the course

When first embarking on a site upgrade, our primary goal is first to figure out what is needed to upgrade Drupal core to 10. Figuring out the best path forward entails working with Composer, a PHP dependency manager that we run from the command line. When you first work with Composer, its output can be as difficult to interpret as sheet music for someone who does not sight-read.

Photo by Weston M on Unsplash

While at times cryptic, Composer’s output can help us craft an initial roadmap if we use the why-not command along with the version of Core we want to upgrade to.

composer why-not drupal/core 10.2.3

Running this command will give us a list of reasons why the site cannot be upgraded to that version of Drupal. Here is a short snippet of the output, which lists several modules that currently require Drupal 9.

acquia/lightning               5.2.2       requires          drupal/core (^9.2.4)…



Nevin Katz

Developer at EDC. I write about web development and biology. Subscribe at for article roundups.