diff --git a/db.php b/db.php
index 6643331..9bc03b3 100644
--- a/db.php
+++ b/db.php
@@ -232,6 +232,13 @@ class hyperdb extends wpdb {
 	 */
 	public $num_failed_queries = 0;
 
+	/**
+	 * Let WordPress know this is a MySQL dropin.
+	 *
+	 * @see https://core.trac.wordpress.org/changeset/19060
+	 */
+	public $is_mysql = true;
+
 	/**
 	 * Gets ready to make database connections
 	 * @param array db class vars