diff --git a/src/SupervisorClient/SupervisorClient.php b/src/SupervisorClient/SupervisorClient.php
index <HASH>..<HASH> 100644
--- a/src/SupervisorClient/SupervisorClient.php
+++ b/src/SupervisorClient/SupervisorClient.php
@@ -222,7 +222,7 @@ class SupervisorClient
 
     // Implementation
 
-    private function _rpcCall($namespace, $method, $args=[])
+    private function _rpcCall($namespace, $method, $args=array())
     {
         if (!is_array($args)) {
             $args = array($args);
Fix default empty array argument that was written in JavaScript syntax instead of PHP.