diff --git a/src/app.yaml b/src/app.yaml
index c21e1ed..1fdcdda 100644
--- a/src/app.yaml
+++ b/src/app.yaml
@@ -1,7 +1,8 @@
 application: google.com:sourceandroid-staging
 version: 1
-runtime: python
+runtime: python27
 api_version: 1
+threadsafe: true
 
 handlers:
 # re-direct to index.html if no path is given