diff --git a/inc/tz/expand.php b/inc/tz/expand.php
index 9a068132..5b8cdff6 100644
--- a/inc/tz/expand.php
+++ b/inc/tz/expand.php
@@ -21,14 +21,14 @@ if ( empty($start) ) $start = sprintf( '%04d-01-01', date('Y'));
 if ( empty($end) )   $end   = sprintf( '%04d-12-31', date('Y') + 10);
 
 $sql = 'SELECT our_tzno, tzid, active, olson_name, vtimezone, etag, ';
-$sql .= 'to_char(last_modified AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
+$sql .= 'to_char((last_modified::timestamp WITH TIME ZONE) AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
 $sql .= 'FROM timezones WHERE tzid=:tzid';
 $params = array( ':tzid' => $tzid );
 $qry = new AwlQuery($sql,$params);
 if ( !$qry->Exec() ) exit(1);
 if ( $qry->rows() < 1 ) {
   $sql = 'SELECT our_tzno, tzid, active, olson_name, vtimezone, etag, ';
-  $sql .= 'to_char(last_modified AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
+  $sql .= 'to_char((last_modified::timestamp WITH TIME ZONE) AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
   $sql .= 'FROM timezones JOIN tz_aliases USING(our_tzno) WHERE tzalias=:tzid';
   if ( !$qry->Exec() ) exit(1);
   if ( $qry->rows() < 1 ) $request->DoResponse(404);
diff --git a/inc/tz/get.php b/inc/tz/get.php
index c5f83c16..6317a988 100644
--- a/inc/tz/get.php
+++ b/inc/tz/get.php
@@ -17,14 +17,14 @@ if ( $format != 'text/calendar' ) {
 }
 
 $sql = 'SELECT our_tzno, tzid, active, olson_name, vtimezone, etag, ';
-$sql .= 'to_char(last_modified AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
+$sql .= 'to_char((last_modified::timestamp WITH TIME ZONE) AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
 $sql .= 'FROM timezones WHERE tzid=:tzid';
 $params = array( ':tzid' => $tzid );
 $qry = new AwlQuery($sql,$params);
 if ( !$qry->Exec() ) exit(1);
 if ( $qry->rows() < 1 ) {
   $sql = 'SELECT our_tzno, tzid, active, olson_name, vtimezone, etag, ';
-  $sql .= 'to_char(last_modified AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
+  $sql .= 'to_char((last_modified::timestamp WITH TIME ZONE) AT TIME ZONE \'UTC\',\'Dy, DD Mon IYYY HH24:MI:SS "GMT"\') AS last_modified ';
   $sql .= 'FROM timezones JOIN tz_aliases USING(our_tzno) WHERE tzalias=:tzid';
   if ( !$qry->Exec() ) exit(1);
   if ( $qry->rows() < 1 ) $request->DoResponse(404);
diff --git a/inc/tz/list.php b/inc/tz/list.php
index de935b4d..8bb4d1fb 100644
--- a/inc/tz/list.php
+++ b/inc/tz/list.php
@@ -15,7 +15,7 @@ $response = new XMLDocument( array("urn:ietf:params:xml:ns:timezone-service" =>
 $tzlist = $response->NewXMLElement('timezone-list');
 $tzlist->NewElement('dtstamp', gmdate('Y-m-d\TH:i:s\Z'));
 
-$sql = 'SELECT our_tzno, tzid, active, to_char(last_modified AT TIME ZONE \'UTC\',\'YYYY-MM-DD\"T\"HH24:MI:SS"Z"\') AS last_modified, olson_name, vtimezone FROM timezones';
+$sql = 'SELECT our_tzno, tzid, active, to_char((last_modified::timestamp WITH TIME ZONE) AT TIME ZONE \'UTC\',\'YYYY-MM-DD\"T\"HH24:MI:SS"Z"\') AS last_modified, olson_name, vtimezone FROM timezones';
 $params = array();
 $where = '';
 if ( $returnall !== true ) {