diff --git a/Aspect_Category_Detection/Xue_MTNA_system/requirements.txt b/Aspect_Category_Detection/Xue_MTNA_system/requirements.txt
index 1797f16..d4ac211 100644
--- a/Aspect_Category_Detection/Xue_MTNA_system/requirements.txt
+++ b/Aspect_Category_Detection/Xue_MTNA_system/requirements.txt
@@ -23,7 +23,7 @@ pyasn1==0.4.8
 pyasn1-modules==0.2.8
 python-dateutil==2.8.1
 pytz==2020.1
-PyYAML==5.3.1
+PyYAML==5.4
 requests==2.24.0
 requests-oauthlib==1.3.0
 rsa==4.6