Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires acquia/drupal-recommended-settings ^1.0 -> satisfiable by acquia/drupal-recommended-settings[1.0.0, 1.0.1]. - acquia/drupal-recommended-settings[1.0.0, ..., 1.0.1] require drush/drush ^11.6 || ^12 -> found drush/drush[11.6.0, 12.0.0, ..., 12.5.3] but it conflicts with your root composer.json require (^13). Problem 2 - Root composer.json requires drupal/core-recommended ^11 -> satisfiable by drupal/core-recommended[11.0.0, ..., 11.0.6]. - drupal/core-recommended[11.0.0, ..., 11.0.6] require sebastian/diff ~5.1.1 -> found sebastian/diff[5.1.1] but these were not loaded, likely because it conflicts with another require.