Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Notice: Trying to access array offset on value of type int in element_children() (line 6600 of /var/www/drupal-7.x/includes/common.inc).
Deprecated function: implode(): Passing glue string after array is deprecated. Swap the parameters in drupal_get_feeds() (line 394 of /var/www/drupal-7.x/includes/common.inc).
Deprecated function: The each() function is deprecated. This message will be suppressed on further calls in menu_set_active_trail() (line 2405 of /var/www/drupal-7.x/includes/menu.inc).
I forget this every time I go to upgrade Drupal, because it's so simple, and spend an hour trying to make absolutely sure I have it right and haven't missed anything. So assuming you're deploying Drupal with git (with the contents of sites/ untracked, presumably), all you have to do is:
git fetch git rebase origin/7.x drush @sites updb
Optionally, you can do a git hard reset to the latest tagged release.