diff --git a/lib/protocol.js b/lib/protocol.js
index b9db95c..a69b77b 100644
--- a/lib/protocol.js
+++ b/lib/protocol.js
@@ -1471,8 +1471,8 @@ function createPacketBuffer(packetId, state, params, isServer) {
     try {
     length += sizeOf(params[fieldInfo.name], fieldInfo, params);
     } catch (e) {
-      console.log(`fieldInfo : ${JSON.stringify(fieldInfo)}`);
-      console.log(`params : ${JSON.stringify(params)}`);
+      console.log("fieldInfo : " + JSON.stringify(fieldInfo));
+      console.log("params : " + JSON.stringify(params));
       throw e;
     }
   });