Upgrade the Code

From the local Drupal site's directory, use Terminus to retrieve the existing site's Git URL:

Add the existing site as a remote repository called existing. Use the URL retrieved in the previous step:

Copy over exported configuration from the original site. From your Drupal site, run the following commands:

Compare your current pantheon.yml file with the new drupal pantheon.upstream.yml:

If you have customizations in your existing site's pantheon.yml that you want to keep for Drupal (e.g., a Quicksilver script or site-specific protected web paths), copy pantheon.yml over:

Copy over any Quicksilver scripts referenced in pantheon.yml:

List contrib modules and themes on your existing site:

The command pm:projectinfo assumes Drush 8. If you encounter an issue with this command, verify and configure the Drush version before you continue.

Use Composer on your new site to add these there:

Copy over any custom modules or themes from your existing site:

Check settings.php for any customizations to copy over:

Copy your files and database from your existing site to the new site:

Push the new codebase from your local machine up to Pantheon:

Run database updates: