diff --git a/books/thoughtful_ml/requirements.txt b/books/thoughtful_ml/requirements.txt
old mode 100755
new mode 100644
index 3d11e0a..985aba0
--- a/books/thoughtful_ml/requirements.txt
+++ b/books/thoughtful_ml/requirements.txt
@@ -25,7 +25,7 @@ nbconvert==5.4.0
 nbformat==4.4.0
 nose==1.3.7
 notebook==5.7.8
-numpy==1.15.1
+numpy==1.22.0
 pandas==0.23.4
 pandocfilters==1.4.2
 parso==0.3.1