When I load certain pages, I get the following error msg: Notice: wpdb::escape is deprecated since version 3.6.0! Use wpdb::prepare() or esc_sql() instead. in /home/myspiritbusiness/public_html/wp-includes/functions.php on line 3829
This is one of the pages: https://myspiritbusiness.com/free-spirit-workbook-4/
What's the best way to fix this, and why did it happen?