$vids = Drupal::entityManager()->getStorage('node')->revisionIds($node);
// Note: sorted ascending by revision id.
        foreach ($vids as $i=>$vid) {
            if ($revision = node_revision_load($vid)) {
                 $recentValues[] = $revision->FIELD_MACHINE_NAME->value;
            }
            if($i==1) break; // if you want two recent  i=0 , i=1
        }

        kint($recentValues);