Minimum schema version I am updating my site from Drupal 8.2.1 to 8.2.4, while running update.php I encounter this problem


  The installed schema version does not meet the minimum.
  Your system schema version is -1. Updating directly from a schema version prior to 8000 is not supported. You must migrate your site to Drupal 8 first.


I am unable to proceed any further. What exactly is causing this problem?
Use Drush. The following commands worked for me.

drush updb -y
drush cr