diff --git a/requirements.txt b/requirements.txt
index d5b5e5a..1662708 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ Cython==0.29.7
 h5py==2.9.0
 joblib==0.13.2
 #matlabengineforpython===R2017b
-nltk==3.4.1
+nltk==3.4.5
 numpy==1.16.2
 pandas==0.24.2
 python-dateutil==2.8.0