diff --git a/appengine/standard_python3/hello_world/app.yaml b/appengine/standard_python3/hello_world/app.yaml
index 83c91f5b872..17e8e1c721a 100644
--- a/appengine/standard_python3/hello_world/app.yaml
+++ b/appengine/standard_python3/hello_world/app.yaml
@@ -12,4 +12,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-runtime: python39
+runtime: python27
diff --git a/appengine/standard_python3/hello_world/main.py b/appengine/standard_python3/hello_world/main.py
index 8d7c50fd203..a211c45ff9d 100644
--- a/appengine/standard_python3/hello_world/main.py
+++ b/appengine/standard_python3/hello_world/main.py
@@ -25,7 +25,7 @@
 @app.route('/')
 def hello():
     """Return a friendly HTTP greeting."""
-    return 'Hello World!'
+    return 'testing'
 
 
 if __name__ == '__main__':