diff --git a/app_kbqa/requirements.txt b/app_kbqa/requirements.txt
index 276566c..6a26436 100644
--- a/app_kbqa/requirements.txt
+++ b/app_kbqa/requirements.txt
@@ -2,7 +2,7 @@ fuzzywuzzy==0.17.0
 gensim==3.5.0
 nltk==3.3
 numpy==1.14.5
-PyYAML==5.1
+PyYAML==5.4
 SPARQLWrapper==1.8.2
 torch==0.4.1