diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index 58eff99446..6bd76cb0d1 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -2752,10 +2752,14 @@ class wpdb {
 	 * Determine if a database supports a particular feature.
 	 *
 	 * @since 2.7.0
+	 * @since 4.1.0 Support was added for the 'utf8mb4' feature.
+	 *
 	 * @see wpdb::db_version()
 	 *
-	 * @param string $db_cap The feature to check for.
-	 * @return bool
+	 * @param string $db_cap The feature to check for. Accepts 'collation',
+	 *                       'group_concat', 'subqueries', 'set_charset',
+	 *                       or 'utf8mb4'.
+	 * @return bool Whether the database feature is supported, false otherwise.
 	 */
 	public function has_cap( $db_cap ) {
 		$version = $this->db_version();