diff --git a/python-udfs/f_sentiment(varchar)/requirements.txt b/python-udfs/f_sentiment(varchar)/requirements.txt
index 886bd48..36997eb 100644
--- a/python-udfs/f_sentiment(varchar)/requirements.txt
+++ b/python-udfs/f_sentiment(varchar)/requirements.txt
@@ -1 +1 @@
-nltk==3.4.5
+nltk==3.6.6