diff --git a/Chapter01/requirements.txt b/Chapter01/requirements.txt
index e9c5350..eb38f24 100644
--- a/Chapter01/requirements.txt
+++ b/Chapter01/requirements.txt
@@ -54,7 +54,7 @@ lxml==4.5.0
 Markdown==3.1.1
 MarkupSafe==1.1.1
 matplotlib==3.1.3
-mistune==0.8.4
+mistune==2.0.3
 nbconvert==5.6.1
 nbformat==5.0.4
 notebook==6.0.3