diff --git a/src/Controller/UserController.php b/src/Controller/UserController.php
index 0f07ee14..78ff39d4 100644
--- a/src/Controller/UserController.php
+++ b/src/Controller/UserController.php
@@ -82,7 +82,7 @@ class UserController extends AdminPages\BaseAdminController
     }
 
     /**
-     * @Route("/{id}", name="user_delete", methods={"DELETE"})
+     * @Route("/{id}", name="user_delete", methods={"DELETE"}, requirements={"id"="\d+"})
      */
     public function delete(Request $request, User $entity, StructuralElementRecursionHelper $recursionHelper)
     {
@@ -153,7 +153,6 @@ class UserController extends AdminPages\BaseAdminController
         ]);
     }
 
-
     /**
      * Get either a Gravatar URL or complete image tag for a specified email address.
      *
diff --git a/src/Controller/UserSettingsController.php b/src/Controller/UserSettingsController.php
index b337fe7d..afc1bfaf 100644
--- a/src/Controller/UserSettingsController.php
+++ b/src/Controller/UserSettingsController.php
@@ -35,13 +35,14 @@ class UserSettingsController extends AbstractController
     public function showBackupCodes()
     {
         $user = $this->getUser();
-        if (!$user instanceof User) {
-            return new \RuntimeException('This controller only works only for Part-DB User objects!');
-        }
 
         //When user change its settings, he should be logged  in fully.
         $this->denyAccessUnlessGranted('IS_AUTHENTICATED_FULLY');
 
+        if (!$user instanceof User) {
+            return new \RuntimeException('This controller only works only for Part-DB User objects!');
+        }
+
         if (empty($user->getBackupCodes())) {
             $this->addFlash('error', 'You do not have any backup codes enabled, therefore you can not view them!');
             throw new Exception('You do not have any backup codes enabled, therefore you can not view them!');
@@ -60,11 +61,14 @@ class UserSettingsController extends AbstractController
     public function removeU2FToken(Request $request, EntityManagerInterface $entityManager, BackupCodeManager $backupCodeManager)
     {
         $user = $this->getUser();
+
+        //When user change its settings, he should be logged  in fully.
+        $this->denyAccessUnlessGranted('IS_AUTHENTICATED_FULLY');
+
         if (!$user instanceof User) {
             throw new \RuntimeException('This controller only works only for Part-DB User objects!');
         }
-        //When user change its settings, he should be logged  in fully.
-        $this->denyAccessUnlessGranted('IS_AUTHENTICATED_FULLY');
+
 
         if ($this->isCsrfTokenValid('delete'.$user->getId(), $request->request->get('_token'))) {
             if($request->request->has('key_id')) {
@@ -101,11 +105,14 @@ class UserSettingsController extends AbstractController
     public function resetTrustedDevices(Request $request, EntityManagerInterface $entityManager)
     {
         $user = $this->getUser();
+
+        //When user change its settings, he should be logged  in fully.
+        $this->denyAccessUnlessGranted('IS_AUTHENTICATED_FULLY');
+
         if (!$user instanceof User) {
             return new \RuntimeException('This controller only works only for Part-DB User objects!');
         }
-        //When user change its settings, he should be logged  in fully.
-        $this->denyAccessUnlessGranted('IS_AUTHENTICATED_FULLY');
+
 
         if ($this->isCsrfTokenValid('devices_reset'.$user->getId(), $request->request->get('_token'))) {
             $user->invalidateTrustedDeviceTokens();
@@ -130,13 +137,13 @@ class UserSettingsController extends AbstractController
 
         $page_need_reload = false;
 
-        if (!$user instanceof User) {
-            return new \RuntimeException('This controller only works only for Part-DB User objects!');
-        }
-
         //When user change its settings, he should be logged  in fully.
         $this->denyAccessUnlessGranted('IS_AUTHENTICATED_FULLY');
 
+        if (!$user instanceof User) {
+            throw new \RuntimeException('This controller only works only for Part-DB User objects!');
+        }
+
         /***************************
          * User settings form
          ***************************/
diff --git a/src/Entity/UserSystem/User.php b/src/Entity/UserSystem/User.php
index 21c20e45..9f60e15f 100644
--- a/src/Entity/UserSystem/User.php
+++ b/src/Entity/UserSystem/User.php
@@ -65,6 +65,7 @@ use Doctrine\ORM\Mapping as ORM;
 use R\U2FTwoFactorBundle\Model\U2F\TwoFactorKeyInterface;
 use Scheb\TwoFactorBundle\Model\BackupCodeInterface;
 use Scheb\TwoFactorBundle\Model\Google\TwoFactorInterface;
+use Scheb\TwoFactorBundle\Model\PreferredProviderInterface;
 use Scheb\TwoFactorBundle\Model\TrustedDeviceInterface;
 use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
 use Symfony\Component\Security\Core\User\UserInterface;
@@ -80,7 +81,7 @@ use R\U2FTwoFactorBundle\Model\U2F\TwoFactorInterface as U2FTwoFactorInterface;
  * @UniqueEntity("name", message="validator.user.username_already_used")
  */
 class User extends AttachmentContainingDBElement implements UserInterface, HasPermissionsInterface,
-    TwoFactorInterface, BackupCodeInterface, TrustedDeviceInterface, U2FTwoFactorInterface
+    TwoFactorInterface, BackupCodeInterface, TrustedDeviceInterface, U2FTwoFactorInterface, PreferredProviderInterface
 {
     use MasterAttachmentTrait;
 
@@ -845,4 +846,18 @@ class User extends AttachmentContainingDBElement implements UserInterface, HasPe
     {
         $this->u2fKeys->removeElement($key);
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function getPreferredTwoFactorProvider(): ?string
+    {
+        //If U2F is available then prefer it
+        if($this->isU2FAuthEnabled()) {
+            return 'u2f_two_factor';
+        }
+
+        //Otherwise use other methods
+        return null;
+    }
 }