diff --git a/requirements.txt b/requirements.txt
index 6dcbf4c..090a8d1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -22,7 +22,7 @@ ipython==2.3.0
 itsdangerous==0.24
 Jinja2==2.8
 kombu==4.0.2
-lxml==3.4.0
+lxml==4.9.1
 MarkupSafe==0.23
 ndg-httpsclient==0.3.2
 numpy==1.8.2