diff --git a/Chapter01/requirements.txt b/Chapter01/requirements.txt
index e9c5350..9955664 100644
--- a/Chapter01/requirements.txt
+++ b/Chapter01/requirements.txt
@@ -50,7 +50,7 @@ jupyterlab-server==1.0.6
 Keras-Applications==1.0.8
 Keras-Preprocessing==1.1.0
 kiwisolver==1.1.0
-lxml==4.5.0
+lxml==4.9.1
 Markdown==3.1.1
 MarkupSafe==1.1.1
 matplotlib==3.1.3