diff --git a/src/interface_py/requirements_runtime_demos.txt b/src/interface_py/requirements_runtime_demos.txt
index 7f7882799..b5fd971fa 100644
--- a/src/interface_py/requirements_runtime_demos.txt
+++ b/src/interface_py/requirements_runtime_demos.txt
@@ -1,4 +1,5 @@
 # for any jupyter demos
+tornado==4.5.3
 ipykernel==4.8.2
 ipython==6.3.1
 ipython_genutils==0.2.0