diff --git a/database.php b/database.php
index e51d64a..ec501e9 100644
--- a/database.php
+++ b/database.php
@@ -80,13 +80,18 @@ Kind regards,
 the voting system.
 
 BODY;
-					$this->notify("Re: ".$decision['tag']." - ".$decision['title'],$body);
+					$this->notify("Re: ".$decision['tag']." - ".$decision['title']." - finalised",$body,$decision['tag']);
 				}
 			}
 		}
-		function notify($subject,$body)
+		function notify($subject,$body,$tag,$first=FALSE)
 		{
-			mail($this->board,$subject,$body,"From: Voting System <returns@cacert.org>");
+			if ($first) {
+				$header = "Message-id: <".$tag.">\r\n";
+			} else {
+				$header = "References: <".$tag.">\r\nIn-reply-to: <".$tag.">\r\n";
+			}
+			mail($this->board,$subject,$body,$header."From: Voting System <returns@cacert.org>");
 			//mail("testsympa@lists.cacert.org",$subject,$body,"From: Voting System <returns@cacert.org>");
 		}
 		function auth()
diff --git a/motion.php b/motion.php
index de94bfd..f2accea 100644
--- a/motion.php
+++ b/motion.php
@@ -72,7 +72,7 @@ again.
 Kind regards,
 the voting system
 BODY;
-					$db->notify("Re: $tag - $title",$body);
+					$db->notify("Re: $tag - $title - modified",$body,$tag);
 				} else {
 					?>
 					<b>The motion has NOT been proposed!</b><br/>
@@ -127,7 +127,7 @@ Abstain: $voteurl&vote=0
 Kind regards,
 the voting system
 BODY;
-					$db->notify("$tag - $title",$body);
+					$db->notify("$tag - $title",$body,$tag,TRUE);
 				} else {
 					?>
 					<b>The motion has NOT been proposed!</b><br/>
diff --git a/motions.php b/motions.php
index ca045ce..2f56af4 100644
--- a/motions.php
+++ b/motions.php
@@ -28,7 +28,7 @@ $content
 Kind regards,
 the voting system
 BODY;
-			$db->notify("Re: $tag - $title - withdrawn",$body);
+			$db->notify("Re: $tag - $title - withdrawn",$body,$tag);
 		}
 		$stmt = $db->getStatement("close decision");
 		$status = -2;
diff --git a/proxy.php b/proxy.php
index ff725cd..f1b837e 100644
--- a/proxy.php
+++ b/proxy.php
@@ -80,7 +80,7 @@ Kind regards,
 the vote system
 
 BODY;
-						$db->notify("Re: $tag - $title",$body);
+						$db->notify("Re: $tag - $title",$body,$tag);
 					} else {
 						?>
 						<b>The vote has NOT been registered.</b><br/>
diff --git a/vote.php b/vote.php
index 126bf4b..022aa40 100644
--- a/vote.php
+++ b/vote.php
@@ -64,7 +64,7 @@ Kind regards,
 the vote system
 
 BODY;
-								//$db->notify("Re: $tag - $title",$body);
+								//$db->notify("Re: $tag - $title",$body,$tag);
 							} else {
 								?>
 								<b>Your vote has NOT been registered.</b><br/>