diff --git a/requirements.txt b/requirements.txt
old mode 100755
new mode 100644
index 46f95ca..07e3a51
--- a/requirements.txt
+++ b/requirements.txt
@@ -52,7 +52,7 @@ Markdown==3.1
 MarkupSafe==1.1.1
 matplotlib==3.0.3
 mccabe==0.6.1
-mistune==0.8.4
+mistune==2.0.3
 mock==3.0.5
 nbconvert==5.5.0
 nbformat==4.4.0