diff --git a/Ch2/ch2-requirements.txt b/Ch2/ch2-requirements.txt
index 520709c..4c81950 100644
--- a/Ch2/ch2-requirements.txt
+++ b/Ch2/ch2-requirements.txt
@@ -10,7 +10,7 @@ treedlib==0.1.3
 numbskull==0.1.1
 tensorflow==1.15
 tensorboard==1.15
-nltk==3.2.5
+nltk==3.6.3
 matplotlib==3.2.2
 wget==3.2
 utils==1.0.1