Drush: Command pm-update needs a higher bootstrap level to run. The drush command 'pm-update' could not be executed.

Submitted by Anonymous (not verified) on Sun, 02/26/2017 - 16:21

I am trying to update Drupal 7 website with Drush. I get this error:

Command pm-update needs a higher bootstrap level to run - you will need to invoke drush from a more functional Drupal environment to run this.

The drush command 'pm-update' could not be executed.

How to solve it?