Customize DDEV: How to Downgrade Terminus and Install Custom Tools in Your Web Container

In a recent guest post for the DDEV blog, Drupal contributor Bill Seremetis of Annertech outlines a practical workaround for DDEV users who need to downgrade bundled tools like Pantheon’s Terminus. The newer versions of Terminus have dropped support for PHP 8.1, which remains in use in many legacy Drupal projects. To address compatibility issues, Seremetis provides a step-by-step method for customizing the DDEV web container using an additional Dockerfile, restoring functionality for older setups.

The post guides readers through creating a Dockerfile to manually install an older Terminus version (3.6.2), thereby bypassing the default DDEV bundle. This technique is especially helpful when tool updates introduce bugs or break compatibility. Seremetis emphasizes that while Terminus is the focus, the method can apply to any command-line tool. The article links to broader DDEV documentation for image customization and package installation.

Expanding the concept, Seremetis also demonstrates how to add entirely new tools—like fzf, a fuzzy finder utility—by defining their versions and using curl and tar to install them in the Docker container. The tutorial is concise but assumes familiarity with Dockerfile syntax and DDEV’s configuration system. While effective, the guide would benefit from more error-handling tips or testing advice. Still, it offers immediate value for developers maintaining diverse or aging environments.