diff --git a/docs/notebook_requirements.txt b/docs/notebook_requirements.txt
index 72dec969..896cbcfd 100644
--- a/docs/notebook_requirements.txt
+++ b/docs/notebook_requirements.txt
@@ -48,7 +48,7 @@ soupsieve==2.6
 terminado==0.18.1
 testpath==0.6.0
 tinycss2==1.3.0
-tornado==6.4.1
+tornado==6.4.2
 traitlets==5.14.3
 wcwidth==0.2.13
 webencodings==0.5.1
diff --git a/docs/sphinx/source/changelog/pending.rst b/docs/sphinx/source/changelog/pending.rst
index 3b602b91..8546499d 100644
--- a/docs/sphinx/source/changelog/pending.rst
+++ b/docs/sphinx/source/changelog/pending.rst
@@ -12,3 +12,8 @@ Bug fixes
 ---------
 * Set marker linewidth to zero in `rdtools.plotting.degradation_summary_plots` (:pull:`433`)
 * Fix :py:func:`~rdtools.normalization.energy_from_power` returns incorrect index for shifted hourly data (:issue:`370`, :pull:`437`)
+
+
+Requirements
+------------
+* Updated tornado==6.4.2 in ``notebook_requirements.txt`` (:pull:`438`)