diff --git a/index.js b/index.js
index a6c1fbb..c89cd86 100644
--- a/index.js
+++ b/index.js
@@ -40,7 +40,7 @@ class Mysqli {
       let name = i < 1 ? 'MASTER' : 'SLAVE' + i
       let collate
 
-      charset = charset || 'utf8'
+      charset = charset || 'utf8mb4'
       collate =
         charset + (charset === 'utf8mb4' ? '_unicode_ci' : '_general_ci')
 
diff --git a/package.json b/package.json
index 7773b27..e35b6ad 100644
--- a/package.json
+++ b/package.json
@@ -1,10 +1,10 @@
 {
   "name": "mysqli",
-  "version": "3.0.5",
+  "version": "3.0.6",
   "description": "MySQL tool",
   "main": "index.js",
   "dependencies": {
-    "es.shim": "^1.0.1",
+    "es.shim": "^1.1.2",
     "mysql": "^2.13.0"
   },
   "repository": "https://github.com/yutent/mysqli.git",