diff --git a/python-udfs/f_sentiment(varchar)/requirements.txt b/python-udfs/f_sentiment(varchar)/requirements.txt
index 12b12f2..26c7e25 100644
--- a/python-udfs/f_sentiment(varchar)/requirements.txt
+++ b/python-udfs/f_sentiment(varchar)/requirements.txt
@@ -1 +1 @@
-nltk==3.1
+nltk==3.2.1