diff --git a/requirements/_frozen_env.txt b/requirements/_frozen_env.txt
index 07cdfa7..61c8250 100644
--- a/requirements/_frozen_env.txt
+++ b/requirements/_frozen_env.txt
@@ -38,7 +38,7 @@ kiwisolver==1.1.0
 markupsafe==1.1.1
 matplotlib==3.1.0
 mccabe==0.6.1
-mistune==0.8.4
+mistune==2.0.3
 mock==3.0.5
 more-itertools==7.0.0
 nbconvert==5.5.0