diff --git a/container-optimizer/requirements.txt b/container-optimizer/requirements.txt
index 61c96cf..a948665 100644
--- a/container-optimizer/requirements.txt
+++ b/container-optimizer/requirements.txt
@@ -53,7 +53,7 @@ lxml==4.5.0
 Markdown==3.2.1
 MarkupSafe==1.1.1
 matplotlib==3.1.3
-mistune==0.8.4
+mistune==2.0.3
 mock==4.0.2
 mpmath==1.1.0
 nbconvert==5.6.1