diff --git a/.themes/classic/source/_includes/custom/category_feed.xml b/.themes/classic/source/_includes/custom/category_feed.xml
index 2f16eee..8c93ed3 100644
--- a/.themes/classic/source/_includes/custom/category_feed.xml
+++ b/.themes/classic/source/_includes/custom/category_feed.xml
@@ -1,5 +1,5 @@
 ---
-layout: nil
+layout: null
 ---
 <?xml version="1.0" encoding="utf-8"?>
 <feed xmlns="http://www.w3.org/2005/Atom">