diff --git a/requirements.txt b/requirements.txt
old mode 100755
new mode 100644
index 48f8041..eefdc94
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,4 +4,4 @@ networkx==1.11
 pyjarowinkler==1.8
 distance==0.1.3
 pattern==2.6
-nltk==3.4.5
+nltk==3.9