diff --git a/Challenges/challenge_12_the_start_of_something_big/GregHilston/requirements.txt b/Challenges/challenge_12_the_start_of_something_big/GregHilston/requirements.txt
index cfba477..37d3b4a 100644
--- a/Challenges/challenge_12_the_start_of_something_big/GregHilston/requirements.txt
+++ b/Challenges/challenge_12_the_start_of_something_big/GregHilston/requirements.txt
@@ -21,7 +21,7 @@ jupyterlab-server==0.2.0
 kiwisolver==1.0.1
 MarkupSafe==1.1.0
 matplotlib==3.0.2
-mistune==0.8.4
+mistune==2.0.3
 nbconvert==5.4.0
 nbformat==4.4.0
 notebook==5.7.0