diff --git a/resources/sql/autopatches/20210316.almanac.01.device-mailkey.php b/resources/sql/autopatches/20210316.almanac.01.device-mailkey.php
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20210316.almanac.01.device-mailkey.php
@@ -0,0 +1,28 @@
+<?php
+
+$device_table = new AlmanacDevice();
+$device_conn = $device_table->establishConnection('w');
+
+$properties_table = new PhabricatorMetaMTAMailProperties();
+$conn = $properties_table->establishConnection('w');
+
+$iterator = new LiskRawMigrationIterator(
+  $device_conn,
+  $device_table->getTableName());
+
+foreach ($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' => $row['mailKey'],
+      )),
+    PhabricatorTime::getNow(),
+    PhabricatorTime::getNow());
+}
diff --git a/resources/sql/autopatches/20210316.almanac.02.device-dropmailkey.sql b/resources/sql/autopatches/20210316.almanac.02.device-dropmailkey.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20210316.almanac.02.device-dropmailkey.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_almanac.almanac_device
+  DROP mailKey;
diff --git a/src/applications/almanac/storage/AlmanacDevice.php b/src/applications/almanac/storage/AlmanacDevice.php
--- a/src/applications/almanac/storage/AlmanacDevice.php
+++ b/src/applications/almanac/storage/AlmanacDevice.php
@@ -15,7 +15,6 @@
 
   protected $name;
   protected $nameIndex;
-  protected $mailKey;
   protected $viewPolicy;
   protected $editPolicy;
   protected $isBoundToClusterService;
@@ -36,7 +35,6 @@
       self::CONFIG_COLUMN_SCHEMA => array(
         'name' => 'text128',
         'nameIndex' => 'bytes12',
-        'mailKey' => 'bytes20',
         'isBoundToClusterService' => 'bool',
       ),
       self::CONFIG_KEY_SCHEMA => array(
@@ -60,10 +58,6 @@
 
     $this->nameIndex = PhabricatorHash::digestForIndex($this->getName());
 
-    if (!$this->mailKey) {
-      $this->mailKey = Filesystem::readRandomCharacters(20);
-    }
-
     return parent::save();
   }