diff --git a/requirements.txt b/requirements.txt
index b22eb80..faed5ef 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -33,7 +33,7 @@ lazr.restfulclient==0.13.3
 lazr.uri==1.0.3
 lockfile==0.8
 louis==2.5.3
-lxml==3.3.3
+lxml==4.9.1
 Mako==0.9.1
 MarkupSafe==0.18
 matplotlib==1.3.1