diff --git a/servant-quickcheck/doc/requirements.txt b/servant-quickcheck/doc/requirements.txt
index 34a7e33e9..e40d1a2bb 100644
--- a/servant-quickcheck/doc/requirements.txt
+++ b/servant-quickcheck/doc/requirements.txt
@@ -20,6 +20,6 @@ snowballstemmer==1.2.1
 Sphinx==1.3.4
 sphinx-autobuild==0.5.2
 sphinx-rtd-theme==0.1.9
-tornado==6.3.3
+tornado==6.4.2
 watchdog==0.8.3
 wheel==0.38.1