diff --git a/requirements.txt b/requirements.txt
index 5254dac..b4c4dd1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -58,7 +58,7 @@ six==1.12.0
 sklearn==0.0
 terminado==0.8.2
 testpath==0.4.2
-tornado==6.0.3
+tornado==6.4.1
 traitlets==4.3.2
 wcwidth==0.1.7
 webencodings==0.5.1