You may be seeing warnings like this if you have WordPress Debug mode enabled:
“Notice: wpdb::escape is deprecated since version 3.6! Use wpdb::prepare() or esc_sql() instead. in /home/USERNAME/public_html/wp-includes/functions.php on line 2913”
I am getting this with WordPress version 3.8.1, and the Domain Mapping plugin wordpress-mu-domain-mapping version 0.5.4.3 but “deprecated” messages happen with many, many plugins.
The wp-includes/functions.php is a WordPress core file. The function at the line mentioned is reporting the error, not the line with the error. To fix the error, you need to know where the error originates. I’m going to show you how to find that. (more…)