With the Drupal 8 end of life in a little over two months and Drupal 10's release next year, this is the time of transitions again at Drupal. However, while Drupal 7 to 8 (or 9) was a big move, the transitions from 8 to 9 and 9 to 10 are much smaller and mostly automated.
Drupal 10 is planned to be released in June, August or December 2022 and the tools are getting ready to support that. The two key tools will be the same as the previous upgrade: Upgrade Status and Drupal Rector.
Matt Glaman has been doing amazing work recently in the underlying components of both tools. Thanks to his work on updating phpstan-drupal for Drupal 10 support, Upgrade Status checks deprecated API uses on Drupal 9 too. Since my last update on that, I added reporting of deprecated modules and new system requirements as well.