Over the last 3 months, Pantheon has rolled out an impressive number of new products and features, not the least of which is a defined pathway to upgrade to Drupal 9 from Drupal 8. Drupal 9 on Pantheon combines modern web technologies of Drupal 9 with powerful tools, security, and automation (hello Autopilot ) that you’ve grown to expect from Pantheon.
Support of Drupal 9 (and continued support of older versions of Drupal) and this collection of products and features has laid the groundwork for future Pantheon releases that will help your website deliver results faster, more reliably, and securely.
The Drupal community as a whole, Pantheon included, has made significant architectural and process changes to aim at the transition from 8 to 9 being easier than previous upgrades. Was that true for you? What was harder than you expected or wanted? What was easier? Where did you get stuck?