diff --git a/requirements.txt b/requirements.txt
index d5b2764..ad249d0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -53,7 +53,7 @@ jupyter-console==5.0.0
 jupyter-core==4.1.0
 kitchen==1.1.1
 lockfile==0.8
-lxml==3.6.1
+lxml==4.9.1
 MarkupSafe==0.11
 matplotlib==1.5.1
 mccabe==0.5.1