diff --git a/requirements.txt b/requirements.txt
index 8904882..0310154 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ jupyter==1.0.0
 jupyter-client==5.3.4
 jupyter-console==6.0.0
 jupyter-core==4.6.1
-lxml==4.2.1
+lxml==4.9.1
 Markdown==3.1.1
 matplotlib==3.1.1
 nbconvert==5.6.1