diff --git a/chapter1/requirements.txt b/chapter1/requirements.txt
index 758bbda..802ef7b 100644
--- a/chapter1/requirements.txt
+++ b/chapter1/requirements.txt
@@ -64,7 +64,7 @@ Jinja2==2.9.5
 jmespath==0.9.0
 jsonschema==2.3.0
 logilab-common==0.62.1
-lxml==3.6.0
+lxml==4.6.5
 M2Crypto==0.22.3
 MarkupSafe==1.0
 matplotlib==2.0.0