diff --git a/requirements.txt b/requirements.txt
old mode 100755
new mode 100644
index 76a999c..c22a746
--- a/requirements.txt
+++ b/requirements.txt
@@ -27,7 +27,7 @@ matplotlib==2.1.2
 msgpack-numpy==0.4.1
 msgpack-python==0.5.1
 murmurhash==0.28.0
-nltk==3.2.5
+nltk==3.4.5
 numpy==1.14.0
 nvidia-ml-py3==7.352.0
 paraphraser==0.1.0a1