In July of 2019 I attended the DrupalCamp in Asheville, NC.  The first day I attended a training class on BackdropCMS.  Backdrop is a fork of Drupal.  Basically it is a new and improved version of Drupal 7 with an easier upgrade path than Drupal 8.  It seemed like a wonderful fit for my organization.  After returning I did the upgrade and worked on the site enough to prove that it would work.  The plan at the moment is to begin using the site in the next fiscal year beginning in October and host it on Pantheon.