The feature to install a new extension from a URL via the Drupal UI has been removed

User Interface changes

The following pages have been removed without replacement:

• The "Add new module" page at /admin/modules/install
• The "Add new theme" page at /admin/theme/install
• The "Add new module or theme" page at /admin/reports/updates/install

Local action links and help text that referred to these pages have also been removed.

This functionality did not use Composer, and so any external dependencies were not installed. This could result in a broken site with required code missing. Furthermore, any extensions installed via this interface could be removed the next time you did use Composer to manage your site.

Using Composer is the only way to safely and correctly add new code to a Drupal installation. Refer to the Drupal guide for using Composer for more information.

Deprecations in 10.4.x and above

1. The Drupal\update\Form\UpdateManagerInstall form is deprecated in 10.4.x and removed from 11.1.x. There is no replacement.
2. The update_authorize_run_install() method is deprecated in 10.4.x and removed from 11.1.x. There is no replacement.

API changes in 11.1.x and above

The core/lib/Drupal/Core/Updater/Updater* classes have been updated since there is no longer a way to install new extensions:

1. The Drupal\Core\Updater\Module class no longer implements postInstallTasks(), relying on the parent class implementation.
2. The Drupal\Core\Updater\Theme class no longer implements no longer implements postInstall() nor postInstallTasks(), relying on the parent class implementation.
3. The following methods in Drupal\Core\Updater\Updater are all deprecated in Drupal 11.1.x and will be removed in Drupal 12.0.x. There are no replacements:
   • install()
   • postInstall()
   • postInstallTasks()
4. Drupal\Core\Updater\UpdaterInterface::postInstall() is marked as deprecated in Drupal 11.1.x and will be removed in Drupal 12.0.0. There is no replacement.