diff --git a/test_data/output/an-untranslated-article.html b/test_data/output/an-untranslated-article.html
index 47f3ba5..880f90e 100644
--- a/test_data/output/an-untranslated-article.html
+++ b/test_data/output/an-untranslated-article.html
@@ -27,7 +27,7 @@
  
   </header>
   <footer class="post-info">
-    <abbr class="published" title="2014-07-14T00:00:00">
+    <abbr class="published" title="2014-07-14T00:00:00+00:00">
       Mon 14 July 2014
     </abbr>
     <address class="vcard author">
diff --git a/test_data/output/cz/an-untranslated-article-en.html b/test_data/output/cz/an-untranslated-article-en.html
index 24395b0..0496de2 100644
--- a/test_data/output/cz/an-untranslated-article-en.html
+++ b/test_data/output/cz/an-untranslated-article-en.html
@@ -26,7 +26,7 @@
  
   </header>
   <footer class="post-info">
-    <abbr class="published" title="2014-07-14T00:00:00">
+    <abbr class="published" title="2014-07-14T00:00:00+00:00">
       Mon 14 July 2014
     </abbr>
     <address class="vcard author">
diff --git a/test_data/output/cz/index.html b/test_data/output/cz/index.html
index e77c698..ed1d7b3 100644
--- a/test_data/output/cz/index.html
+++ b/test_data/output/cz/index.html
@@ -21,7 +21,7 @@
         <li><article class="hentry">
                 <header> <h2 class="entry-title"><a href="http://example.com/test/cz/translated-article.html" rel="bookmark" title="Permalink to Přeložený článek">Přeložený článek</a></h2> </header>
                 <footer class="post-info">
-                    <abbr class="published" title="2014-09-15T00:00:00"> Mon 15 September 2014 </abbr>
+                    <abbr class="published" title="2014-09-15T00:00:00+00:00"> Mon 15 September 2014 </abbr>
                     <address class="vcard author">By
                         <a class="url fn" href="http://example.com/test/cz/author/test-testovic.html">Test Testovič</a>
                     </address>
@@ -33,7 +33,7 @@ Zde je odkaz na <a class="reference external" href="http://example.com/test/cz/.
         <li><article class="hentry">
                 <header> <h2 class="entry-title"><a href="http://example.com/test/cz/an-untranslated-article-en.html" rel="bookmark" title="Permalink to An untranslated article">An untranslated article</a></h2> </header>
                 <footer class="post-info">
-                    <abbr class="published" title="2014-07-14T00:00:00"> Mon 14 July 2014 </abbr>
+                    <abbr class="published" title="2014-07-14T00:00:00+00:00"> Mon 14 July 2014 </abbr>
                     <address class="vcard author">By
                         <a class="url fn" href="http://example.com/test/cz/author/test-testovic.html">Test Testovič</a>
                     </address>
diff --git a/test_data/output/cz/translated-article.html b/test_data/output/cz/translated-article.html
index f8c2abb..935ee2a 100644
--- a/test_data/output/cz/translated-article.html
+++ b/test_data/output/cz/translated-article.html
@@ -29,7 +29,7 @@
 
   </header>
   <footer class="post-info">
-    <abbr class="published" title="2014-09-15T00:00:00">
+    <abbr class="published" title="2014-09-15T00:00:00+00:00">
       Mon 15 September 2014
     </abbr>
     <address class="vcard author">
diff --git a/test_data/output/de/drafts/an-untranslated-article-en.html b/test_data/output/de/drafts/an-untranslated-article-en.html
index 6291665..e37ba3f 100644
--- a/test_data/output/de/drafts/an-untranslated-article-en.html
+++ b/test_data/output/de/drafts/an-untranslated-article-en.html
@@ -26,7 +26,7 @@
  
   </header>
   <footer class="post-info">
-    <abbr class="published" title="2014-07-14T00:00:00">
+    <abbr class="published" title="2014-07-14T00:00:00+00:00">
       Mo 14 Juli 2014
     </abbr>
     <address class="vcard author">
diff --git a/test_data/output/de/index.html b/test_data/output/de/index.html
index 3eb5f2a..75e8cce 100644
--- a/test_data/output/de/index.html
+++ b/test_data/output/de/index.html
@@ -21,7 +21,7 @@
         <li><article class="hentry">
                 <header> <h2 class="entry-title"><a href="http://example.com/test/de/translated-article.html" rel="bookmark" title="Permalink to Ein übersetzter Artikel">Ein übersetzter Artikel</a></h2> </header>
                 <footer class="post-info">
-                    <abbr class="published" title="2014-09-14T00:00:00"> So 14 September 2014 </abbr>
+                    <abbr class="published" title="2014-09-14T00:00:00+00:00"> So 14 September 2014 </abbr>
                     <address class="vcard author">By
                         <a class="url fn" href="http://example.com/test/de/author/der-tester.html">Der Tester</a>
                     </address>
diff --git a/test_data/output/de/translated-article.html b/test_data/output/de/translated-article.html
index edb46b6..4c501a9 100644
--- a/test_data/output/de/translated-article.html
+++ b/test_data/output/de/translated-article.html
@@ -29,7 +29,7 @@
 
   </header>
   <footer class="post-info">
-    <abbr class="published" title="2014-09-14T00:00:00">
+    <abbr class="published" title="2014-09-14T00:00:00+00:00">
       So 14 September 2014
     </abbr>
     <address class="vcard author">
diff --git a/test_data/output/index.html b/test_data/output/index.html
index 892e88c..30a9b50 100644
--- a/test_data/output/index.html
+++ b/test_data/output/index.html
@@ -22,7 +22,7 @@
         <li><article class="hentry">
                 <header> <h2 class="entry-title"><a href="http://example.com/test/translated-article.html" rel="bookmark" title="Permalink to A translated article">A translated article</a></h2> </header>
                 <footer class="post-info">
-                    <abbr class="published" title="2014-09-13T00:00:00"> Sat 13 September 2014 </abbr>
+                    <abbr class="published" title="2014-09-13T00:00:00+00:00"> Sat 13 September 2014 </abbr>
                     <address class="vcard author">By
                         <a class="url fn" href="http://example.com/test/author/the-tester.html">The Tester</a>
                     </address>
@@ -34,7 +34,7 @@ Here is a link to <a class="reference external" href="http://example.com/test/im
         <li><article class="hentry">
                 <header> <h2 class="entry-title"><a href="http://example.com/test/an-untranslated-article.html" rel="bookmark" title="Permalink to An untranslated article">An untranslated article</a></h2> </header>
                 <footer class="post-info">
-                    <abbr class="published" title="2014-07-14T00:00:00"> Mon 14 July 2014 </abbr>
+                    <abbr class="published" title="2014-07-14T00:00:00+00:00"> Mon 14 July 2014 </abbr>
                     <address class="vcard author">By
                         <a class="url fn" href="http://example.com/test/author/the-tester.html">The Tester</a>
                     </address>
diff --git a/test_data/output/translated-article.html b/test_data/output/translated-article.html
index 38e702d..81eb863 100644
--- a/test_data/output/translated-article.html
+++ b/test_data/output/translated-article.html
@@ -30,7 +30,7 @@
 
   </header>
   <footer class="post-info">
-    <abbr class="published" title="2014-09-13T00:00:00">
+    <abbr class="published" title="2014-09-13T00:00:00+00:00">
       Sat 13 September 2014
     </abbr>
     <address class="vcard author">