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..c4c0f87 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
@@ -24,7 +24,7 @@ matplotlib==3.0.2
 mistune==0.8.4
 nbconvert==5.4.0
 nbformat==4.4.0
-notebook==5.7.0
+notebook==6.4.12
 numpy==1.15.4
 pandas==0.23.4
 pandocfilters==1.4.2