diff --git a/examples/timeseries/timeseries_requirements.txt b/examples/timeseries/timeseries_requirements.txt
index d79436e..ab5dcab 100644
--- a/examples/timeseries/timeseries_requirements.txt
+++ b/examples/timeseries/timeseries_requirements.txt
@@ -25,7 +25,7 @@ matplotlib==2.1.0
 mistune==0.8
 nbconvert==5.3.1
 nbformat==4.4.0
-nltk==3.2.5
+nltk==3.6.3
 notebook==5.2.0
 numpy==1.13.3
 pandas==0.22