diff --git a/atom/blog.xml b/atom/blog.xml
index 547b821..1718d5d 100644
--- a/atom/blog.xml
+++ b/atom/blog.xml
@@ -8,7 +8,7 @@
         <email>baruchel@sdf.org</email>
     </author>
     <rights>CC BY-SA 4.0</rights>
-    <updated>2022-11-05T15:32:51</updated>
+    <updated>2022-11-05T14:38:33+00:00Z</updated>
     <link href="https://git.sdf.org/baruchel/feeds/raw/branch/master/src/blog.rst" />
     <link href="https://git.sdf.org/baruchel/feeds/raw/branch/master/atom/blog.xml" rel="self" />
     <generator uri="https://git.sdf.org/baruchel/feeds/src/branch/master/rst2atom.py">rst2atom</generator>
@@ -16,7 +16,7 @@
     <entry>
         <title>Initial entry</title>
         <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
-        <updated>2022-11-05T00:00:00</updated>
+        <updated>2022-11-05T00:00:00Z</updated>
         <content type="xhtml">
             <div xmlns="http://www.w3.org/1999/xhtml"><div class="section" id="initial-entry">
 <h1>Initial entry</h1>
diff --git a/rst2atom.py b/rst2atom.py
index 8342c13..b8711cc 100644
--- a/rst2atom.py
+++ b/rst2atom.py
@@ -43,7 +43,7 @@ def extract_meta(html):
 
 def find_date(d):
     """
-    Parse the comments in a <div> section and return a an ISO8601 formatted
+    Parse the comments in a <div> section and return a an RFC 3339 formatted
     string being the first recognized date string.
     Raise dateutil.parser.ParserError if no such comment contains a date.
 
@@ -60,7 +60,7 @@ def find_date(d):
         for k in c.extract().split(" "):
             try:
                 t = dateutil.parser.parse(k)
-                return t.isoformat(timespec='seconds')
+                return t.isoformat(timespec='seconds') + "Z"
             except dateutil.parser.ParserError:
                 pass
     raise dateutil.parser.ParserError
@@ -118,7 +118,7 @@ print("""<?xml version="1.0" encoding="utf-8"?>
          docinfos["Author:"],
          docinfos["Contact:"],
          meta["copyright"],
-         datetime.datetime.now().isoformat(timespec='seconds'),
+         datetime.datetime.now(datetime.timezone.utc).isoformat(timespec='seconds') + "Z",
          meta["original-source"],
          meta["syndication-source"],
          generator_uri, generator_name