Lullabot: How and When to Upgrade from Drupal 7 to Drupal 9

If you’re one of the 70% of Drupal sites that are still on Drupal 7 at the time of this writing, you may be wondering what the upgrade path looks like to go from Drupal 7 to Drupal 9. What does the major lift look like to jump ahead two Drupal versions? How is this different than if you’d upgraded to Drupal 8 sometime in the last few years? And how long will it be before you have to do it again?