diff --git a/src/Core/System.php b/src/Core/System.php
index 37e6d8a1cb..67ee3a8038 100644
--- a/src/Core/System.php
+++ b/src/Core/System.php
@@ -140,7 +140,7 @@ class System
 	 * @param string  $content_type Type of the input (Default: 'application/json').
 	 * @param integer $options JSON options
 	 */
-	public static function jsonExit($x, $content_type = 'application/json', int $options = null) {
+	public static function jsonExit($x, $content_type = 'application/json', int $options = 0) {
 		header("Content-type: $content_type");
 		echo json_encode($x, $options);
 		exit();