Does Drush 8.x work with core 7.x? With the major changes to Drupal with version 8, it seems I would need Drush 7.x or earlier to work with Drupal 7.x. I tried to rebuild the cache and I got errors related to namespaces in PHP. It seemed to be looking for features that were not part of Drupal 7.x.

Are there different commands to clear the cache for a Drupal 7.x site?
I tried drush cr and it came back with errors indicating it was trying to find code using namespaces, but Drupal 7.x core doesn't use namespaces in the code.

I tried it on Ubuntu and on Windows.
Yes, Drush 8 works with Drupal 6, 7 and -8.3. I just tested Drush 8.1.17 against a Drupal 7.58 site: worked a charm to clear cache, generate a login URL and download a module.

This is the compatibility table from their site for reference:




  I mean are there different commands to clear the cache for a Drupal 7.x site?


Yes, it was cache-clear, or cc for short in Drupal 7, e.g.

drush cc all