Although the end-of-life for Drupal 7 might have been extended by one year to Nov 2023, now is the time to start preparing for migrating your site to Drupal 9. However, migrations can be daunting, even if you have only one site. But what if you have 20 sites? 50? 100? How can you do it at scale? For this session, we will be drawing on lessons learnt during the amalgamation of 50 of University of Limerick’s sites into one Drupal 9 platform. This saw the migration of more than 60,000 nodes spanning 70 content types, 95 paragraph types and over 60 vocabularies, and which resulted in more than 3,700 individual migration processes! In this session we’ll cover: * How to work with the Migrate API rather than fight against it * Why we recommend rebuilding rather than upgrading * Preparing for migrations * Migrating from Paragraphs/Field Collections into Layout Builder * Tips and advice for migrating at scale * Management and tracking of a large migration project This session is aimed at developers who have some experience with migrations, but not necessarily at scale, and are looking for a more advanced discussion on the topic.