diff --git a/docs/requirements.txt b/docs/requirements.txt
index b371094..794099e 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -91,7 +91,7 @@ MarkupSafe==1.0
 matplotlib==2.2.2
 mccabe==0.6.1
 MinimalModbus==0.7
-mistune==0.8.3
+mistune==2.0.3
 monotonic==1.5
 Naked==0.1.31
 nbconvert==5.3.1