Working great with WordPress 4.7.5 and PHP 7.
Fix for Query Monitor
The Query Monitor plugin, and some other plugins, uses the $db->use_mysqli bool variable to detect if the driver support PDO (_mysqli functions), which is the case for SQLite Integration. But because the $use_mysqli variable is not defined in the PDODB class, this check fails.
To fix it, simply declare the variable like this in the PDODB.CLASS.PHP file, right before the constructor function:
* @var bool Support PHP MySQL Improved version.
* @access public
* @author Guy Dumais (https://guydumais.digital)
public $use_mysqli = true;