diff --git a/.eleventy.js b/.eleventy.js
index 45530f3..d49d1d4 100644
--- a/.eleventy.js
+++ b/.eleventy.js
@@ -325,6 +325,11 @@ module.exports = function (eleventyConfig) {
       singleTags: ["link"]
     }  
   });
+
+  eleventyConfig.addFilter("dateToZulu", function(date){
+    if(!date) return "";
+    return new Date(date).toISOString("dd-MM-yyyyTHH:mm:ssZ");
+  });
   eleventyConfig.addFilter("jsonify", function (variable) {
     return JSON.stringify(variable) || '""';
   });
diff --git a/src/site/feed.njk b/src/site/feed.njk
index cfe346d..f08f4d7 100644
--- a/src/site/feed.njk
+++ b/src/site/feed.njk
@@ -18,7 +18,7 @@
                 {% else %}{{ note.fileSlug }}
                 {% endif %}
             </title>
-            <updated>{{ (note.updated or note.date ) | dateToRfc3339 }}</updated>
+            <updated>{%if note.data.updated %}{{ note.data.updated | dateToZulu }}{%else%}{{ note.date | dateToRfc3339 }}{%endif%}</updated>
             <id>{{ meta.siteBaseUrl }}{{note.url | url }}</id>
             <content type="html">
                 {{ note.templateContent | hideDataview | link | taggify | htmlToAbsoluteUrls(meta.siteBaseUrl) }}