diff --git a/UPGRADE.md b/UPGRADE.md
index bc43e419..6904dea5 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -1,9 +1,3 @@
-# TODO
-
-- remove dependency on laminas/laminas-httphandlerrunner
-- create a bridge towards SSP utility classes, so they can be easily mocked
-- move away from SSP database as store; move to DBAL
-- move to phpstan instead of psalm (as SSP)
 
 # Version 5 to 6
 
@@ -97,11 +91,13 @@ Below are also some internal changes that should not have impact for the OIDC OP
 this module as a library or extending from it, you will probably encounter breaking changes, since a lot of code
 has been refactored:
 
-- upgraded to v5 of lcobucci/jwt https://github.com/lcobucci/jwt
-- upgraded to v3 of laminas/laminas-diactoros https://github.com/laminas/laminas-diactoros
+- Upgraded to v5 of lcobucci/jwt https://github.com/lcobucci/jwt
+- Upgraded to v3 of laminas/laminas-diactoros https://github.com/laminas/laminas-diactoros
 - SimpleSAMLphp version used during development was bumped to v2.3
 - In Authorization Code Flow, a new validation was added which checks for 'openid' value in 'scope' parameter. Up to
 now, 'openid' value was dynamically added if not present. In Implicit Code Flow this validation was already present. 
+- Removed importer from legacy OAuth2 module, as it is very unlikely that someone will upgrade from legacy OAuth2
+module to v6 of oidc module. If needed, one can upgrade to earlier versions of oidc module, and then to v6.
 
 # Version 4 to 5
 
diff --git a/src/Services/Container.php b/src/Services/Container.php
index 8a6c5dae..0e3bf969 100644
--- a/src/Services/Container.php
+++ b/src/Services/Container.php
@@ -317,9 +317,6 @@ public function __construct()
         $databaseMigration = new DatabaseMigration($database);
         $this->services[DatabaseMigration::class] = $databaseMigration;
 
-        $databaseLegacyOAuth2Import = new DatabaseLegacyOAuth2Import($clientRepository, $clientEntityFactory);
-        $this->services[DatabaseLegacyOAuth2Import::class] = $databaseLegacyOAuth2Import;
-
         $authenticationService = new AuthenticationService(
             $userRepository,
             $authSimpleFactory,
diff --git a/src/Services/DatabaseLegacyOAuth2Import.php b/src/Services/DatabaseLegacyOAuth2Import.php
deleted file mode 100644
index cfd6ec3f..00000000
--- a/src/Services/DatabaseLegacyOAuth2Import.php
+++ /dev/null
@@ -1,66 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-/*
- * This file is part of the simplesamlphp-module-oidc.
- *
- * Copyright (C) 2018 by the Spanish Research and Academic Network.
- *
- * This code was developed by Universidad de Córdoba (UCO https://www.uco.es)
- * for the RedIRIS SIR service (SIR: http://www.rediris.es/sir)
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-namespace SimpleSAML\Module\oidc\Services;
-
-use SimpleSAML\Module\oidc\Factories\Entities\ClientEntityFactory;
-use SimpleSAML\Module\oidc\Repositories\ClientRepository;
-use SimpleSAML\Modules\OAuth2\Repositories\ClientRepository as OAuth2ClientRepository;
-
-/**
- * Class DatabaseLegacyOAuth2Import.
- */
-class DatabaseLegacyOAuth2Import
-{
-    public function __construct(
-        private readonly ClientRepository $clientRepository,
-        private readonly ClientEntityFactory $clientEntityFactory,
-    ) {
-    }
-
-    /**
-     * @psalm-suppress UndefinedClass, MixedAssignment, MixedArrayAccess, MixedArgument
-     * @throws \JsonException
-     * @throws \SimpleSAML\Module\oidc\Server\Exceptions\OidcServerException
-     */
-    public function import(): void
-    {
-        if (!class_exists(ClientRepository::class)) {
-            return;
-        }
-
-        $oauth2ClientRepository = new OAuth2ClientRepository();
-        $clients = $oauth2ClientRepository->findAll();
-
-        foreach ($clients as $client) {
-            if ($this->clientRepository->findById($client['id'])) {
-                continue;
-            }
-
-            $this->clientRepository->add($this->clientEntityFactory->fromData(
-                $client['id'],
-                $client['secret'],
-                $client['name'],
-                $client['description'],
-                $client['redirect_uri'],
-                $client['scopes'],
-                true,
-                false,
-                $client['auth_source'],
-            ));
-        }
-    }
-}