--- dokuwiki/inc/html.php~	2010-01-11 14:35:04.000000000 +0200
+++ dokuwiki/inc/html.php	2010-01-11 14:35:07.213389784 +0200
@@ -862,8 +862,12 @@
     // given as rev and rev2 parameters, with rev2 being optional. Or in an
     // array in rev2.
     $rev1 = $REV;
+	// handle $r1 + $r2, see DW #1821
+	if (isset($_REQUEST['r1']) && isset($_REQUEST['r2'])) {
+        $rev1 = (int) $_REQUEST['r1'];
+        $rev2 = (int) $_REQUEST['r2'];
 
-    if(is_array($_REQUEST['rev2'])){
+	} else if(is_array($_REQUEST['rev2'])){
         $rev1 = (int) $_REQUEST['rev2'][0];
         $rev2 = (int) $_REQUEST['rev2'][1];
 
--- dokuwiki/inc/common.php~	2010-01-11 14:48:54.000000000 +0200
+++ dokuwiki/inc/common.php	2010-01-11 14:48:58.213308444 +0200
@@ -1128,6 +1128,8 @@
   }elseif($rev){
     $subject = $lang['mail_changed'].' '.$id;
     $text = str_replace('@OLDPAGE@',wl($id,"rev=$rev",true,'&'),$text);
+    $rev2 = $INFO['meta']['date']['modified'];
+    $text = str_replace('@DIFFPAGE@',wl($id,"do=diff&r1=$rev&r2=$rev2",true,'&'),$text);
     require_once(DOKU_INC.'inc/DifferenceEngine.php');
     $df  = new Diff(explode("\n",rawWiki($id,$rev)),
                     explode("\n",rawWiki($id)));