diff --git a/requirements.txt b/requirements.txt
index 72f6c37..43e4420 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -29,7 +29,7 @@ ipaddress==1.0.16
 isort==4.2.5
 lazy-object-proxy==1.2.2
 lockfile==0.12.2
-lxml==3.5.0
+lxml==4.9.1
 Mako==1.0.3
 MarkupSafe==0.23
 matplotlib==1.5.1