diff --git a/requirements.txt b/requirements.txt
index a626768..3f889da 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -39,7 +39,7 @@ isodate==0.5.4
 itsdangerous==0.24
 Jinja2==2.8
 jmespath==0.9.0
-lxml==3.6.4
+lxml==4.9.1
 Mako==1.0.4
 Markdown==2.6.6
 MarkupSafe==0.23