diff --git a/message/classes/task/migrate_message_data.php b/message/classes/task/migrate_message_data.php
index 7b7235858fd..e81dee0a3d6 100644
--- a/message/classes/task/migrate_message_data.php
+++ b/message/classes/task/migrate_message_data.php
@@ -132,7 +132,7 @@ class migrate_message_data extends \core\task\adhoc_task {
         $messages = $DB->get_recordset_select('message', $select, $params, 'id ASC');
         foreach ($messages as $message) {
             if ($message->notification) {
-                $this->migrate_notification($message);
+                $this->migrate_notification($message, false);
             } else {
                 $this->migrate_message($conversationid, $message);
             }
@@ -146,7 +146,7 @@ class migrate_message_data extends \core\task\adhoc_task {
         $messages = $DB->get_recordset_select('message_read', $select, $params, 'id ASC');
         foreach ($messages as $message) {
             if ($message->notification) {
-                $this->migrate_notification($message);
+                $this->migrate_notification($message, true);
             } else {
                 $this->migrate_message($conversationid, $message);
             }
@@ -161,9 +161,10 @@ class migrate_message_data extends \core\task\adhoc_task {
      * Helper function to deal with migrating an individual notification.
      *
      * @param \stdClass $notification
+     * @param bool $isread Was the notification read?
      * @throws \dml_exception
      */
-    private function migrate_notification($notification) {
+    private function migrate_notification($notification, $isread) {
         global $DB;
 
         $tabledata = new \stdClass();
@@ -181,7 +182,16 @@ class migrate_message_data extends \core\task\adhoc_task {
         $tabledata->timeread = $notification->timeread ?? null;
         $tabledata->timecreated = $notification->timecreated;
 
-        $DB->insert_record('notifications', $tabledata);
+        $newid = $DB->insert_record('notifications', $tabledata);
+
+        // Check if there is a record to move to the new 'message_popup_notifications' table.
+        if ($mp = $DB->get_record('message_popup', ['messageid' => $notification->id, 'isread' => (int) $isread])) {
+            $mpn = new \stdClass();
+            $mpn->notificationid = $newid;
+            $DB->insert_record('message_popup_notifications', $mpn);
+
+            $DB->delete_records('message_popup', ['id' => $mp->id]);
+        }
     }
 
     /**
diff --git a/message/tests/migrate_message_data_task_test.php b/message/tests/migrate_message_data_task_test.php
index 7094a899011..72c1d0a245a 100644
--- a/message/tests/migrate_message_data_task_test.php
+++ b/message/tests/migrate_message_data_task_test.php
@@ -107,6 +107,8 @@ class core_message_migrate_message_data_task_testcase extends advanced_testcase
         $this->assertEquals(2, $DB->count_records('message'));
         $this->assertEquals(1, $DB->count_records('message_read'));
         $this->assertEquals(6, $DB->count_records('messages'));
+        $this->assertEquals(0, $DB->count_records('notifications'));
+        $this->assertEquals(0, $DB->count_records('message_popup_notifications'));
 
         // Get the conversations.
         $conversation1 = \core_message\api::get_conversation_between_users([$user1->id, $user2->id]);
@@ -224,12 +226,18 @@ class core_message_migrate_message_data_task_testcase extends advanced_testcase
         // Remember - we are only converting the notifications related to user 1.
         $this->assertEquals(2, $DB->count_records('message'));
         $this->assertEquals(1, $DB->count_records('message_read'));
+        $this->assertEquals(3, $DB->count_records('message_popup'));
         $this->assertEquals(6, $DB->count_records('notifications'));
+        $this->assertEquals(6, $DB->count_records('message_popup_notifications'));
 
         // Confirm what we have in the notifications table is correct.
         $notifications = $DB->get_records('notifications', [], 'timecreated ASC');
+        $popupnotifications = $DB->get_records('message_popup_notifications', [], 'notificationid ASC', 'notificationid');
         $i = 1;
         foreach ($notifications as $notification) {
+            // Assert the correct id is stored in the 'message_popup_notifications' table.
+            $this->assertArrayHasKey($notification->id, $popupnotifications);
+
             $useridfrom = $user1->id;
             $useridto = $user2->id;
             if ($i > 3) {
@@ -309,6 +317,17 @@ class core_message_migrate_message_data_task_testcase extends advanced_testcase
         $tabledata->smallmessage = 'Small message ' . $timecreated;
         $tabledata->timecreated = $timecreated;
 
-        return $DB->insert_record($table, $tabledata);
+        $id = $DB->insert_record($table, $tabledata);
+
+        // Insert into the legacy 'message_popup' table if it is a notification.
+        if ($notification) {
+            $mp = new stdClass();
+            $mp->messageid = $id;
+            $mp->isread = (!is_null($timeread)) ? 1 : 0;
+
+            $DB->insert_record('message_popup', $mp);
+        }
+
+        return $id;
     }
 }