Merge branch 'develop'
diff --git a/README.md b/README.md
index bbcb2fb..507ecf0 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,10 @@
 
 ## Versions
 
+### v0.3.1
+
+- use INVALID_APP_NAME as default appName in engine.json
+
 ### v0.3.0
 
 - update for PredictionIO 0.9.2, including:
diff --git a/engine.json b/engine.json
index 10b284f..1da14e1 100644
--- a/engine.json
+++ b/engine.json
@@ -4,14 +4,14 @@
   "engineFactory": "org.template.ecommercerecommendation.ECommerceRecommendationEngine",
   "datasource": {
     "params" : {
-      "appName": ""
+      "appName": "INVALID_APP_NAME"
     }
   },
   "algorithms": [
     {
       "name": "als",
       "params": {
-        "appName": "",
+        "appName": "INVALID_APP_NAME",
         "unseenOnly": true,
         "seenEvents": ["buy", "view"],
         "rank": 10,