diff --git a/src/feed.njk b/src/feed.njk
index 1ae2d37..568abca 100644
--- a/src/feed.njk
+++ b/src/feed.njk
@@ -17,7 +17,7 @@ metadata:
   <subtitle>{{ metadata.subtitle }}</subtitle>
   <link href="{{ permalink | absoluteUrl(metadata.url) }}" rel="self"/>
   <link href="{{ metadata.url }}"/>
-  <updated>{{ page.date | makeRfc822Date }}</updated>
+  <updated>{{ page.date | dateToRfc3339 }}</updated>
   <id>{{ metadata.url }}</id>
   <author>
     <name>{{ metadata.author.name }}</name>