diff --git a/settings/Controller/ChangePasswordController.php b/settings/Controller/ChangePasswordController.php
index 31ff8904ce..208178d567 100644
--- a/settings/Controller/ChangePasswordController.php
+++ b/settings/Controller/ChangePasswordController.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 /**
  *
  *
@@ -26,12 +27,12 @@
  */
 namespace OC\Settings\Controller;
 
+use OC\Group\Manager as GroupManager;
 use OC\HintException;
 use OC\User\Session;
 use OCP\App\IAppManager;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http\JSONResponse;
-use OCP\IGroupManager;
 use OCP\IL10N;
 use OCP\IRequest;
 use OCP\IUser;
@@ -49,7 +50,7 @@ class ChangePasswordController extends Controller {
 	/** @var IL10N */
 	private $l;
 
-	/** @var IGroupManager */
+	/** @var GroupManager */
 	private $groupManager;
 
 	/** @var Session */
@@ -58,24 +59,12 @@ class ChangePasswordController extends Controller {
 	/** @var IAppManager */
 	private $appManager;
 
-	/**
-	 * ChangePasswordController constructor.
-	 *
-	 * @param string $appName
-	 * @param IRequest $request
-	 * @param $userId
-	 * @param IUserManager $userManager
-	 * @param IUserSession $userSession
-	 * @param IGroupManager $groupManager
-	 * @param IAppManager $appManager
-	 * @param IL10N $l
-	 */
-	public function __construct($appName,
+	public function __construct(string $appName,
 								IRequest $request,
-								$userId,
+								string $userId,
 								IUserManager $userManager,
 								IUserSession $userSession,
-								IGroupManager $groupManager,
+								GroupManager $groupManager,
 								IAppManager $appManager,
 								IL10N $l) {
 		parent::__construct($appName, $request);
@@ -98,7 +87,7 @@ class ChangePasswordController extends Controller {
 	 *
 	 * @return JSONResponse
 	 */
-	public function changePersonalPassword($oldpassword = '', $newpassword = null) {
+	public function changePersonalPassword(string $oldpassword = '', string $newpassword = null): JSONResponse {
 		/** @var IUser $user */
 		$user = $this->userManager->checkPassword($this->userId, $oldpassword);
 		if ($user === false) {
@@ -148,7 +137,7 @@ class ChangePasswordController extends Controller {
 	 *
 	 * @return JSONResponse
 	 */
-	public function changeUserPassword($username = null, $password = null, $recoveryPassword = null) {
+	public function changeUserPassword(string $username = null, string $password = null, string $recoveryPassword = null): JSONResponse {
 		if ($username === null) {
 			return new JSONResponse([
 				'status' => 'error',