diff --git a/requirements_py3_matteo.txt b/requirements_py3_matteo.txt
index e962deb..bd36e34 100644
--- a/requirements_py3_matteo.txt
+++ b/requirements_py3_matteo.txt
@@ -51,7 +51,7 @@ mccabe==0.6.1
 memory-profiler==0.47
 mongoengine==0.12.0
 multiprocess==0.70.5
-nltk==3.2.2
+nltk==3.4.5
 numpy==1.12.1
 openpyxl==2.4.7
 packaging==16.8
diff --git a/requirements_py3_refactored.txt b/requirements_py3_refactored.txt
old mode 100755
new mode 100644
index a5d4d22..644b0c9
--- a/requirements_py3_refactored.txt
+++ b/requirements_py3_refactored.txt
@@ -74,7 +74,7 @@ msgpack==0.5.6
 multiprocess==0.70.5
 nbconvert==5.3.1
 nbformat==4.4.0
-nltk==3.2.2
+nltk==3.4.5
 notebook==5.5.0
 numpy==1.12.1
 openpyxl==2.4.7