This guide will show you how to migrate a Drupal 8 Composer-managed site currently hosted outside of Pantheon to a Drupal 9 Composer-managed site on Pantheon. If you to want upgrade to a Drupal 9 site, use Migrate a Composer Managed Drupal 9 Site from Another Platforminstead.
This upgrade migrates your existing site to a new site. The new site will not maintain your site’s commit history.
This doc uses the following aliases:
- Old site folder
You have access to a local copy of the existing site and/or you have access to a Git repository of the existing site.
Your site is based on the drupal/recommended-project template or a similar non-composer managed structure.