diff --git a/requirement.txt b/requirement.txt
index 646c3fc..c0295f0 100644
--- a/requirement.txt
+++ b/requirement.txt
@@ -12,7 +12,7 @@ pandas==0.23.4
 python-crfsuite==0.9.5
 python-dateutil==2.7.3
 pytz==2018.5
-PyYAML==3.13
+PyYAML==5.4
 requests==2.19.1
 six==1.11.0
 underthesea==1.1.8