diff --git a/admin/migration.php b/admin/migration.php
index 25bc733..1a85f65 100644
--- a/admin/migration.php
+++ b/admin/migration.php
@@ -22,6 +22,7 @@ use Framadate\Migration\From_0_8_to_0_9_Migration;
 use Framadate\Migration\AddColumn_receiveNewComments_For_0_9;
 use Framadate\Migration\AddColumn_uniqId_In_vote_For_0_9;
 use Framadate\Migration\AddColumn_hidden_In_poll_For_0_9;
+use Framadate\Migration\Generate_uniqId_for_old_votes;
 use Framadate\Migration\Migration;
 use Framadate\Utils;
 
@@ -36,6 +37,7 @@ $migrations = [
     new AddColumn_receiveNewComments_For_0_9(),
     new AddColumn_uniqId_In_vote_For_0_9(),
     new AddColumn_hidden_In_poll_For_0_9(),
+    new Generate_uniqId_for_old_votes(),
 ];
 // ---------------------------------------
 
diff --git a/app/classes/Framadate/Migration/Generate_uniqId_for_old_votes.php b/app/classes/Framadate/Migration/Generate_uniqId_for_old_votes.php
new file mode 100644
index 0000000..4814e9f
--- /dev/null
+++ b/app/classes/Framadate/Migration/Generate_uniqId_for_old_votes.php
@@ -0,0 +1,83 @@
+<?php
+/**
+ * This software is governed by the CeCILL-B license. If a copy of this license
+ * is not distributed with this file, you can obtain one at
+ * http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.txt
+ *
+ * Authors of STUdS (initial project): Guilhem BORGHESI (borghesi@unistra.fr) and Raphaël DROZ
+ * Authors of Framadate/OpenSondate: Framasoft (https://github.com/framasoft)
+ *
+ * =============================
+ *
+ * Ce logiciel est régi par la licence CeCILL-B. Si une copie de cette licence
+ * ne se trouve pas avec ce fichier vous pouvez l'obtenir sur
+ * http://www.cecill.info/licences/Licence_CeCILL-B_V1-fr.txt
+ *
+ * Auteurs de STUdS (projet initial) : Guilhem BORGHESI (borghesi@unistra.fr) et Raphaël DROZ
+ * Auteurs de Framadate/OpenSondage : Framasoft (https://github.com/framasoft)
+ */
+namespace Framadate\Migration;
+
+use Framadate\Security\Token;
+use Framadate\Utils;
+
+/**
+ * This migration generate uniqId for all legacy votes.
+ *
+ * @package Framadate\Migration
+ * @version 0.9
+ */
+class Generate_uniqId_for_old_votes implements Migration {
+
+    function __construct() {
+    }
+
+    function description() {
+        return 'Generate "uniqId" in "vote" table for all legacy votes';
+    }
+
+    function preCondition(\PDO $pdo) {
+        $stmt = $pdo->query('SHOW TABLES');
+        $tables = $stmt->fetchAll(\PDO::FETCH_COLUMN);
+
+        // Check if tables of v0.9 are presents
+        $diff = array_diff([Utils::table('poll'), Utils::table('slot'), Utils::table('vote'), Utils::table('comment')], $tables);
+        return count($diff) === 0;
+    }
+
+    /**
+     * This methode is called only one time in the migration page.
+     *
+     * @param \PDO $pdo The connection to database
+     * @return bool true is the execution succeeded
+     */
+    function execute(\PDO $pdo) {
+
+        $pdo->beginTransaction();
+        $this->generateUniqIdsForEmptyOnes($pdo);
+        $pdo->commit();
+
+        return true;
+    }
+
+    private function generateUniqIdsForEmptyOnes($pdo) {
+        $select = $pdo->query('
+SELECT `id`
+  FROM `' . Utils::table('vote') . '`
+ WHERE `uniqid` = \'\'');
+
+        $update = $pdo->prepare('
+UPDATE `' . Utils::table('vote') . '`
+   SET `uniqid` = :uniqid
+ WHERE `id` = :id');
+
+        while ($row = $select->fetch(\PDO::FETCH_OBJ)) {
+            $token = Token::getToken(16);
+            $update->execute([
+                'uniqid' => $token,
+                'id' => $row->id
+                             ]);
+        }
+    }
+
+}