diff --git a/src/applications/conpherence/mail/ConpherenceReplyHandler.php b/src/applications/conpherence/mail/ConpherenceReplyHandler.php
index 83385146f4..c695cfbc39 100644
--- a/src/applications/conpherence/mail/ConpherenceReplyHandler.php
+++ b/src/applications/conpherence/mail/ConpherenceReplyHandler.php
@@ -1,94 +1,94 @@
 <?php
 
 final class ConpherenceReplyHandler extends PhabricatorMailReplyHandler {
 
   private $mailAddedParticipantPHIDs;
 
   public function setMailAddedParticipantPHIDs(array $phids) {
     $this->mailAddedParticipantPHIDs = $phids;
     return $this;
   }
   public function getMailAddedParticipantPHIDs() {
     return $this->mailAddedParticipantPHIDs;
   }
 
   public function validateMailReceiver($mail_receiver) {
     if (!($mail_receiver instanceof ConpherenceThread)) {
       throw new Exception('Mail receiver is not a ConpherenceThread!');
     }
   }
 
   public function getPrivateReplyHandlerEmailAddress(
     PhabricatorObjectHandle $handle) {
-    return $this->getDefaultPrivateReplyHandlerEmailAddress($handle, 'E');
+    return $this->getDefaultPrivateReplyHandlerEmailAddress($handle, 'Z');
   }
 
   public function getPublicReplyHandlerEmailAddress() {
-    return $this->getDefaultPublicReplyHandlerEmailAddress('E');
+    return $this->getDefaultPublicReplyHandlerEmailAddress('Z');
   }
 
   public function getReplyHandlerInstructions() {
     if ($this->supportsReplies()) {
       return pht('Reply to comment and attach files.');
     } else {
       return null;
     }
   }
 
   protected function receiveEmail(PhabricatorMetaMTAReceivedMail $mail) {
     $conpherence = $this->getMailReceiver();
     $user = $this->getActor();
     if (!$conpherence->getPHID()) {
       $conpherence
         ->attachParticipants(array())
         ->attachFilePHIDs(array());
     } else {
       $edge_type = PhabricatorObjectHasFileEdgeType::EDGECONST;
       $file_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
         $conpherence->getPHID(),
         $edge_type);
       $conpherence->attachFilePHIDs($file_phids);
       $participants = id(new ConpherenceParticipant())
         ->loadAllWhere('conpherencePHID = %s', $conpherence->getPHID());
       $participants = mpull($participants, null, 'getParticipantPHID');
       $conpherence->attachParticipants($participants);
     }
 
     $content_source = PhabricatorContentSource::newForSource(
       PhabricatorContentSource::SOURCE_EMAIL,
       array(
         'id' => $mail->getID(),
       ));
 
     $editor = id(new ConpherenceEditor())
       ->setActor($user)
       ->setContentSource($content_source)
       ->setParentMessageID($mail->getMessageID());
 
     $body = $mail->getCleanTextBody();
     $file_phids = $mail->getAttachments();
     $body = $this->enhanceBodyWithAttachments(
       $body,
       $file_phids,
       '{F%d}');
 
     $xactions = array();
     if ($this->getMailAddedParticipantPHIDs()) {
       $xactions[] = id(new ConpherenceTransaction())
         ->setTransactionType(ConpherenceTransactionType::TYPE_PARTICIPANTS)
         ->setNewValue(array('+' => $this->getMailAddedParticipantPHIDs()));
     }
 
     $xactions = array_merge(
       $xactions,
       $editor->generateTransactionsFromText(
         $user,
         $conpherence,
         $body));
 
     $editor->applyTransactions($conpherence, $xactions);
 
     return $conpherence;
   }
 
 }
diff --git a/src/applications/conpherence/mail/ConpherenceThreadMailReceiver.php b/src/applications/conpherence/mail/ConpherenceThreadMailReceiver.php
index 71f78745df..a340980928 100644
--- a/src/applications/conpherence/mail/ConpherenceThreadMailReceiver.php
+++ b/src/applications/conpherence/mail/ConpherenceThreadMailReceiver.php
@@ -1,38 +1,40 @@
 <?php
 
 final class ConpherenceThreadMailReceiver
   extends PhabricatorObjectMailReceiver {
 
   public function isEnabled() {
     $app_class = 'PhabricatorConpherenceApplication';
     return PhabricatorApplication::isClassInstalled($app_class);
   }
 
   protected function getObjectPattern() {
-    return 'E[1-9]\d*';
+    // TODO: Only recognize "Z" once we get closer to shipping Calendar.
+    return '[EZ][1-9]\d*';
   }
 
   protected function loadObject($pattern, PhabricatorUser $viewer) {
-    $id = (int)trim($pattern, 'E');
+    // TODO: Only recognize "Z" once we get closer to shipping Calendar.
+    $id = (int)trim($pattern, 'EZ');
 
     return id(new ConpherenceThreadQuery())
       ->setViewer($viewer)
       ->withIDs(array($id))
       ->executeOne();
   }
 
   protected function processReceivedObjectMail(
     PhabricatorMetaMTAReceivedMail $mail,
     PhabricatorLiskDAO $object,
     PhabricatorUser $sender) {
 
     $handler = id(new ConpherenceReplyHandler())
       ->setMailReceiver($object);
 
     $handler->setActor($sender);
     $handler->setExcludeMailRecipientPHIDs(
       $mail->loadExcludeMailRecipientPHIDs());
     $handler->processEmail($mail);
   }
 
 }