diff --git a/requirements.txt b/requirements.txt
old mode 100755
new mode 100644
index bd866e0..446e762
--- a/requirements.txt
+++ b/requirements.txt
@@ -48,7 +48,7 @@ lxml==4.2.3
 Markdown==2.6.11
 MarkupSafe==1.0
 matplotlib==2.2.2
-mistune==0.8.3
+mistune==2.0.3
 more-itertools==4.2.0
 mpi4py==3.0.0
 mujoco-py==1.50.1.56