diff --git a/resources/sql/autopatches/20210316.almanac.07.binding-mailkey.php b/resources/sql/autopatches/20210316.almanac.07.binding-mailkey.php
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20210316.almanac.07.binding-mailkey.php
@@ -0,0 +1,28 @@
+<?php
+
+$binding_table = new AlmanacBinding();
+$binding_conn = $binding_table->establishConnection('w');
+
+$properties_table = new PhabricatorMetaMTAMailProperties();
+$conn = $properties_table->establishConnection('w');
+
+$iterator = new LiskRawMigrationIterator(
+  $binding_conn,
+  $binding_table->getTableName());
+
+foreach ($iterator as $row) {
+  queryfx(
+    $conn,
+    'INSERT IGNORE INTO %R
+        (objectPHID, mailProperties, dateCreated, dateModified)
+      VALUES
+        (%s, %s, %d, %d)',
+    $properties_table,
+    $row['phid'],
+    phutil_json_encode(
+      array(
+        'mailKey' => $row['mailKey'],
+      )),
+    PhabricatorTime::getNow(),
+    PhabricatorTime::getNow());
+}
diff --git a/resources/sql/autopatches/20210316.almanac.08.binding-dropmailkey.sql b/resources/sql/autopatches/20210316.almanac.08.binding-dropmailkey.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20210316.almanac.08.binding-dropmailkey.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_almanac.almanac_binding
+  DROP mailKey;
diff --git a/src/applications/almanac/storage/AlmanacBinding.php b/src/applications/almanac/storage/AlmanacBinding.php
--- a/src/applications/almanac/storage/AlmanacBinding.php
+++ b/src/applications/almanac/storage/AlmanacBinding.php
@@ -13,7 +13,6 @@
   protected $servicePHID;
   protected $devicePHID;
   protected $interfacePHID;
-  protected $mailKey;
   protected $isDisabled;
 
   private $service = self::ATTACHABLE;
@@ -33,7 +32,6 @@
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_COLUMN_SCHEMA => array(
-        'mailKey' => 'bytes20',
         'isDisabled' => 'bool',
       ),
       self::CONFIG_KEY_SCHEMA => array(
@@ -51,15 +49,8 @@
     ) + parent::getConfiguration();
   }
 
-  public function generatePHID() {
-    return PhabricatorPHID::generateNewPHID(AlmanacBindingPHIDType::TYPECONST);
-  }
-
-  public function save() {
-    if (!$this->mailKey) {
-      $this->mailKey = Filesystem::readRandomCharacters(20);
-    }
-    return parent::save();
+  public function getPHIDType() {
+    return AlmanacBindingPHIDType::TYPECONST;
   }
 
   public function getName() {
@@ -67,7 +58,9 @@
   }
 
   public function getURI() {
-    return '/almanac/binding/'.$this->getID().'/';
+    return urisprintf(
+      '/almanac/binding/%s/',
+      $this->getID());
   }
 
   public function getService() {