diff --git a/nucypher/requirements.txt b/nucypher/requirements.txt
index 5bde247..3a2a3b4 100644
--- a/nucypher/requirements.txt
+++ b/nucypher/requirements.txt
@@ -110,7 +110,7 @@ marshmallow==3.6.1
 matplotlib==3.2.1
 maya==0.6.1
 mccabe==0.6.1
-mistune==0.8.4
+mistune==2.0.3
 monotonic==1.5
 more-itertools==4.2.0
 msgpack-python==0.5.6