diff --git a/NLP/Conversational-Recommendation-BASELINE/requirements.txt b/NLP/Conversational-Recommendation-BASELINE/requirements.txt
index 33c256eb4..4364cfe69 100644
--- a/NLP/Conversational-Recommendation-BASELINE/requirements.txt
+++ b/NLP/Conversational-Recommendation-BASELINE/requirements.txt
@@ -21,7 +21,7 @@ jieba==0.42.1
 jmespath==0.9.5
 kiwisolver==1.1.0
 matplotlib==2.2.3
-nltk==3.4
+nltk==3.6.6
 numpy==1.16.1
 objgraph==3.4.1
 opencv-python==4.1.1.26