diff --git a/books/zero_to_deep_learning/requirements.txt b/books/zero_to_deep_learning/requirements.txt
old mode 100755
new mode 100644
index b5ad23a..685d96d
--- a/books/zero_to_deep_learning/requirements.txt
+++ b/books/zero_to_deep_learning/requirements.txt
@@ -37,7 +37,7 @@ MarkupSafe==1.0
 matplotlib==2.2.2
 mistune==0.8.3
 more-itertools==4.2.0
-nbconvert==5.3.1
+nbconvert==6.5.1
 nbformat==4.4.0
 notebook==5.7.8
 numpy==1.14.5