diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index cbec91c3d..4fcc5c4af 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -1,10 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * SPDX-FileCopyrightText: 2017 Nextcloud GmbH and Nextcloud contributors
  * SPDX-License-Identifier: AGPL-3.0-or-later
  */
-
 namespace OCA\Guests\AppInfo;
 
 use OCA\Files\Event\LoadAdditionalScriptsEvent;
diff --git a/lib/AppWhitelist.php b/lib/AppWhitelist.php
index 1ee5ee807..7fc2f9a47 100644
--- a/lib/AppWhitelist.php
+++ b/lib/AppWhitelist.php
@@ -25,6 +25,7 @@
  */
 class AppWhitelist {
 	private readonly string $baseUrl;
+
 	private readonly int $baseUrlLength;
 
 	public const WHITELIST_ALWAYS = ',core,theming,settings,avatar,files,heartbeat,dav,guests,impersonate,accessibility,terms_of_service,dashboard,weather_status,user_status,apporder,twofactor_totp,twofactor_webauthn,twofactor_backupcodes,twofactor_nextcloud_notification';
@@ -60,15 +61,16 @@ public function isUrlAllowed(IUser $user, string|false $url): bool {
 
 			if ($this->isAppWhitelisted($app)) {
 				return true;
-			} else {
-				if ($url === '/apps/files_external/api/v1/mounts') {
-					// fake successful response
-					echo '[]';
-					exit;
-				}
-				$this->logger->notice("Blocking access to non-whitelisted app ($app) for guest", ['app' => 'guests']);
-				return false;
 			}
+
+			if ($url === '/apps/files_external/api/v1/mounts') {
+				// fake successful response
+				echo '[]';
+				exit;
+			}
+
+			$this->logger->notice('Blocking access to non-whitelisted app (' . $app . ') for guest', ['app' => 'guests']);
+			return false;
 		}
 
 		return true;
@@ -92,40 +94,69 @@ private function getRequestedApp(string|false $url): string {
 		if (substr($url, 0, $this->baseUrlLength) === $this->baseUrl) {
 			$url = substr($url, $this->baseUrlLength);
 		}
+
 		if (str_starts_with($url, '/index.php/')) {
 			$url = substr($url, 10);
 		}
+
 		if (str_starts_with($url, '/apps/')) {
 			// empty string / 'apps' / $app / rest of the route
 			[, , $app,] = explode('/', $url, 4);
 			return \OC_App::cleanAppId($app);
-		} elseif ($url === '/cron.php') {
+		}
+
+		if ($url === '/cron.php') {
 			return 'core';
-		} elseif (str_starts_with($url, '/core/')) {
+		}
+
+		if (str_starts_with($url, '/core/')) {
 			return 'core';
-		} elseif (str_starts_with($url, '/js/')) {
+		}
+
+		if (str_starts_with($url, '/js/')) {
 			return 'core';
-		} elseif (str_starts_with($url, '/css/')) {
+		}
+
+		if (str_starts_with($url, '/css/')) {
 			return 'core';
-		} elseif (str_starts_with($url, '/login')) {
+		}
+
+		if (str_starts_with($url, '/login')) {
 			return 'core';
-		} elseif (str_starts_with($url, '/logout')) {
+		}
+
+		if (str_starts_with($url, '/logout')) {
 			return 'core';
-		} elseif (str_starts_with($url, '/f/')) {
+		}
+
+		if (str_starts_with($url, '/f/')) {
 			return 'files';
-		} elseif (str_starts_with($url, '/webdav/')) {
+		}
+
+		if (str_starts_with($url, '/webdav/')) {
 			return 'dav';
-		} elseif (str_starts_with($url, '/dav/')) {
+		}
+
+		if (str_starts_with($url, '/dav/')) {
 			return 'dav';
-		} elseif (str_starts_with($url, '/call/')) {
+		}
+
+		if (str_starts_with($url, '/call/')) {
 			return 'spreed';
-		} elseif (str_starts_with($url, '/settings/')) {
+		}
+
+		if (str_starts_with($url, '/settings/')) {
 			return 'settings';
-		} elseif (str_starts_with($url, '/avatar/')) {
+		}
+
+		if (str_starts_with($url, '/avatar/')) {
 			return 'avatar';
-		} elseif (str_starts_with($url, '/heartbeat')) {
+		}
+
+		if (str_starts_with($url, '/heartbeat')) {
 			return 'heartbeat';
 		}
+
 		return 'core';
 	}
 
diff --git a/lib/BackgroundJob/TransferJob.php b/lib/BackgroundJob/TransferJob.php
index 8f6706cba..e06ba0eac 100644
--- a/lib/BackgroundJob/TransferJob.php
+++ b/lib/BackgroundJob/TransferJob.php
@@ -74,6 +74,7 @@ private function fail(Transfer $transfer, ?IUser $targetUser = null): void {
 		if (!$targetUser instanceof IUser) {
 			return;
 		}
+
 		$result = $targetUser->delete(); // Rollback created user
 		if (!$result) {
 			$this->logger->error('Failed to delete target user', ['user' => $targetUser->getUID()]);
@@ -86,6 +87,7 @@ public function run($argument): void {
 
 		$transfer = $this->transferMapper->getById($id);
 		$transfer->setStatus(Transfer::STATUS_STARTED);
+
 		$this->transferMapper->update($transfer);
 
 		$source = $transfer->getSource();
@@ -99,7 +101,7 @@ public function run($argument): void {
 		}
 
 		if ($this->userManager->userExists($target)) {
-			$this->logger->error("Cannot transfer guest user \"$source\", target user \"$target\" already exists");
+			$this->logger->error('Cannot transfer guest user "' . $source . '", target user "' . $target . '" already exists');
 			$this->fail($transfer);
 			return;
 		}
@@ -119,8 +121,8 @@ public function run($argument): void {
 
 		try {
 			$this->transferService->transfer($sourceUser, $targetUser);
-		} catch (\Throwable $th) {
-			$this->logger->error($th->getMessage(), ['exception' => $th]);
+		} catch (\Throwable $throwable) {
+			$this->logger->error($throwable->getMessage(), ['exception' => $throwable]);
 			$this->fail($transfer, $targetUser);
 			return;
 		}
diff --git a/lib/Capabilities.php b/lib/Capabilities.php
index 436167676..b92b11309 100644
--- a/lib/Capabilities.php
+++ b/lib/Capabilities.php
@@ -20,6 +20,7 @@ class Capabilities implements ICapability {
 
 	/**
 	 * @inheritDoc
+	 * @return array<string, array<string, bool>>
 	 */
 	public function getCapabilities(): array {
 		return [
diff --git a/lib/Command/AddCommand.php b/lib/Command/AddCommand.php
index 8882b04a7..703ca1165 100644
--- a/lib/Command/AddCommand.php
+++ b/lib/Command/AddCommand.php
@@ -134,7 +134,6 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 			$input->getOption('language') ?? '',
 			$password
 		);
-
 		if ($user instanceof IUser) {
 			$output->writeln('<info>The guest account user "' . $user->getUID() . '" was created successfully</info>');
 			return self::SUCCESS;
diff --git a/lib/Command/ListCommand.php b/lib/Command/ListCommand.php
index 0fc9371eb..e7c516005 100644
--- a/lib/Command/ListCommand.php
+++ b/lib/Command/ListCommand.php
@@ -35,12 +35,13 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 		$guests = $this->guestManager->getGuestsInfo();
 
 		$outputType = $input->getOption('output');
-		if (count($guests) === 0) {
+		if ($guests === []) {
 			if ($outputType === self::OUTPUT_FORMAT_JSON || $outputType === self::OUTPUT_FORMAT_JSON_PRETTY) {
 				$output->writeln('[]');
 			} else {
 				$output->writeln('<info>No guests created</info>');
 			}
+
 			return self::SUCCESS;
 		}
 
@@ -52,6 +53,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 			$table->setRows($guests);
 			$table->render();
 		}
+
 		return self::SUCCESS;
 	}
 }
diff --git a/lib/Config.php b/lib/Config.php
index 278afbdbc..83cd8b076 100644
--- a/lib/Config.php
+++ b/lib/Config.php
@@ -65,6 +65,7 @@ public function setAppWhitelist(array|string $whitelist): void {
 		if (is_array($whitelist)) {
 			$whitelist = implode(',', $whitelist);
 		}
+
 		$this->appConfig->setAppValueString('whitelist', $whitelist);
 	}
 
@@ -87,10 +88,10 @@ public function canCreateGuests(): bool {
 		// Check if we have a group restriction
 		// and if the user belong to that group
 		$groupRestriction = $this->getCreateRestrictedToGroup();
-		if (!empty($groupRestriction)) {
+		if ($groupRestriction !== []) {
 			$userGroups = $this->groupManager->getUserGroupIds($user);
 			$groupRestriction = array_intersect($userGroups, $groupRestriction);
-			if (empty($groupRestriction)) {
+			if ($groupRestriction === []) {
 				return false;
 			}
 		}
diff --git a/lib/Controller/APIController.php b/lib/Controller/APIController.php
index 84ab60d0b..cd6371345 100644
--- a/lib/Controller/APIController.php
+++ b/lib/Controller/APIController.php
@@ -65,7 +65,7 @@ public function languages(): DataResponse {
 			// Put appropriate languages into appropriate arrays, to print them sorted
 			// common languages -> divider -> other languages
 			if (in_array($lang, Factory::COMMON_LANGUAGE_CODES)) {
-				$commonLanguages[array_search($lang, Factory::COMMON_LANGUAGE_CODES)] = $ln;
+				$commonLanguages[array_search($lang, Factory::COMMON_LANGUAGE_CODES, true)] = $ln;
 			} else {
 				$languages[] = $ln;
 			}
@@ -79,10 +79,12 @@ public function languages(): DataResponse {
 				// If a doesn't have a name, but b does, list b before a
 				return 1;
 			}
+
 			if ($a['code'] !== $a['name'] && $b['code'] === $b['name']) {
 				// If a does have a name, but b doesn't, list a before b
 				return -1;
 			}
+
 			// Otherwise compare the names
 			return strcmp((string)$a['name'], (string)$b['name']);
 		});
@@ -102,6 +104,7 @@ public function groups(): DataResponse {
 		} else {
 			$groups = $this->subAdmin->getSubAdminsGroups($user);
 		}
+
 		$groups = array_values(array_map(fn (IGroup $group): array => [
 			'gid' => $group->getGID(),
 			'name' => $group->getDisplayName(),
diff --git a/lib/Controller/UsersController.php b/lib/Controller/UsersController.php
index f91ceeb00..96c1cf7e7 100644
--- a/lib/Controller/UsersController.php
+++ b/lib/Controller/UsersController.php
@@ -87,23 +87,25 @@ public function create(string $email, string $displayName, string $language, arr
 			if (!$group) {
 				return new DataResponse(
 					[
-						'errorMessages' => ["Group $groupId not found"],
+						'errorMessages' => ['Group ' . $groupId . ' not found'],
 					],
 					Http::STATUS_BAD_REQUEST
 				);
 			}
-			if (!($this->subAdmin->isSubAdminOfGroup($currentUser, $group) || $this->groupManager->isAdmin($currentUser->getUID()))) {
+
+			if (!$this->subAdmin->isSubAdminOfGroup($currentUser, $group) && !$this->groupManager->isAdmin($currentUser->getUID())) {
 				return new DataResponse(
 					[
-						'errorMessages' => ["You are not allowed to add users to group $groupId"],
+						'errorMessages' => ['You are not allowed to add users to group ' . $groupId],
 					],
 					Http::STATUS_FORBIDDEN
 				);
 			}
+
 			$groupObjects[] = $group;
 		}
 
-		if (empty($email) || !$this->mailer->validateMailAddress($email)) {
+		if ($email === '' || !$this->mailer->validateMailAddress($email)) {
 			$errorMessages['email'] = $this->l10n->t(
 				'Invalid mail address'
 			);
@@ -122,7 +124,7 @@ public function create(string $email, string $displayName, string $language, arr
 			);
 		}
 
-		if (!empty($errorMessages)) {
+		if ($errorMessages !== []) {
 			return new DataResponse(
 				[
 					'errorMessages' => $errorMessages,
@@ -132,18 +134,26 @@ public function create(string $email, string $displayName, string $language, arr
 		}
 
 		try {
-			$this->guestManager->createGuest($this->userSession->getUser(), $username, $email, $displayName, $language);
-			$guestUser = $this->userManager->get($username);
+			$guestUser = $this->guestManager->createGuest($this->userSession->getUser(), $username, $email, $displayName, $language);
+			if (!$guestUser instanceof IUser) {
+				return new DataResponse(
+					[
+						'errorMessages' => ['email' => 'Unable to create guest user ' . $username],
+					],
+					Http::STATUS_UNPROCESSABLE_ENTITY
+				);
+			}
 			if ($this->userManager instanceof PublicEmitter) {
 				$this->userManager->emit('\OC\User', 'assignedUserId', [$username]);
 			}
+
 			foreach ($groupObjects as $group) {
 				$group->addUser($guestUser);
 			}
-		} catch (\Exception $e) {
+		} catch (\Exception $exception) {
 			return new DataResponse(
 				[
-					'errorMessages' => ['email' => $e->getMessage()],
+					'errorMessages' => ['email' => $exception->getMessage()],
 				],
 				Http::STATUS_UNPROCESSABLE_ENTITY
 			);
diff --git a/lib/Db/Transfer.php b/lib/Db/Transfer.php
index a034549ac..23523b813 100644
--- a/lib/Db/Transfer.php
+++ b/lib/Db/Transfer.php
@@ -26,6 +26,7 @@
  */
 class Transfer extends Entity {
 	public const STATUS_WAITING = 'waiting';
+
 	public const STATUS_STARTED = 'started';
 
 	/** @var string */
diff --git a/lib/FilteredNavigationManager.php b/lib/FilteredNavigationManager.php
index d04f1c72e..70e7f7e98 100644
--- a/lib/FilteredNavigationManager.php
+++ b/lib/FilteredNavigationManager.php
@@ -28,6 +28,9 @@ public function getAll(string $type = 'link'): array {
 		return array_filter($items, $this->isEntryWhitelisted(...));
 	}
 
+	/**
+	 * @param array<string, mixed> $item
+	 */
 	private function isEntryWhitelisted(array $item): bool {
 		return $this->whitelist->isUrlAllowed($this->user, $item['href']);
 	}
diff --git a/lib/GroupBackend.php b/lib/GroupBackend.php
index eac2281e1..03730fae3 100644
--- a/lib/GroupBackend.php
+++ b/lib/GroupBackend.php
@@ -34,7 +34,7 @@ public function __construct(
 	}
 
 	private function getMembers(): array {
-		if (empty($this->guestMembers)) {
+		if ($this->guestMembers === []) {
 			$this->guestMembers = $this->guestManager->listGuests();
 		}
 
@@ -111,6 +111,7 @@ public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0): arra
 			if ($this->guestManager->isGuest() && $this->config->hideOtherUsers()) {
 				return [$this->userSession->getUser()->getUID()];
 			}
+
 			return $offset === 0 ? $this->getMembers() : [];
 		}
 
@@ -122,8 +123,10 @@ public function countUsersInGroup(string $gid, string $search = ''): int {
 			if ($this->guestManager->isGuest() && $this->config->hideOtherUsers()) {
 				return 1;
 			}
+
 			return count($this->getMembers());
 		}
+
 		return 0;
 	}
 
@@ -131,6 +134,7 @@ public function getGroupDetails(string $gid): array {
 		if ($gid === $this->groupName) {
 			return ['displayName' => 'Guests'];
 		}
+
 		return [];
 	}
 
diff --git a/lib/GuestManager.php b/lib/GuestManager.php
index b5ce2fc14..0cd2fcfc6 100644
--- a/lib/GuestManager.php
+++ b/lib/GuestManager.php
@@ -41,15 +41,16 @@ public function isGuest(IUser|string|null $user = null): bool {
 			$user = $this->userSession->getUser();
 			return ($user !== null) && $this->userBackend->userExists($user->getUID());
 		}
+
 		if (is_string($user)) {
 			return $this->userBackend->userExists($user);
-		} elseif ($user instanceof IUser) {
-			return $this->userBackend->userExists($user->getUID());
 		}
-		return false;
+
+
+		return $this->userBackend->userExists($user->getUID());
 	}
 
-	public function createGuest(?IUser $createdBy, string $userId, string $email, string $displayName = '', string $language = '', ?string $initialPassword = null) : IUser {
+	public function createGuest(?IUser $createdBy, string $userId, string $email, string $displayName = '', string $language = '', ?string $initialPassword = null) : ?IUser {
 		if ($initialPassword === null) {
 			$passwordEvent = new GenerateSecurePasswordEvent();
 			$this->eventDispatcher->dispatchTyped($passwordEvent);
@@ -58,23 +59,26 @@ public function createGuest(?IUser $createdBy, string $userId, string $email, st
 			$password = $initialPassword;
 		}
 
-		/** @var IUser */
 		$user = $this->userManager->createUserFromBackend(
 			$userId,
 			$password,
 			$this->userBackend
 		);
 
+		if (!$user instanceof IUser) {
+			return null;
+		}
+
 		$user->setSystemEMailAddress($email);
-		if ($createdBy) {
+		if ($createdBy instanceof IUser) {
 			$this->config->setUserValue($userId, 'guests', 'created_by', $createdBy->getUID());
 		}
 
-		if ($displayName) {
+		if ($displayName !== '') {
 			$user->setDisplayName($displayName);
 		}
 
-		if ($language) {
+		if ($language !== '') {
 			$this->config->setUserValue($userId, 'core', 'lang', $language);
 		}
 
@@ -111,6 +115,15 @@ public function listGuests(): array {
 		return $this->userBackend->getUsers();
 	}
 
+	/**
+	 * @return list<array{
+	 *     email: non-empty-string,
+	 *     display_name: non-empty-string,
+	 *     created_by: string,
+	 *     share_count: int,
+	 *     share_count_with_circles: int
+	 * }>
+	 */
 	public function getGuestsInfo(): array {
 		$displayNames = $this->userBackend->getDisplayNames();
 		$guests = array_keys($displayNames);
@@ -134,6 +147,10 @@ public function getGuestsInfo(): array {
 		}, $guests);
 	}
 
+	/**
+	 * @param list<string> $guests
+	 * @return array<string, int>
+	 */
 	private function getShareCountForUsers(array $guests): array {
 		$query = $this->connection->getQueryBuilder();
 		$query->select('share_with', $query->func()->count('*', 'count'))
@@ -143,13 +160,23 @@ private function getShareCountForUsers(array $guests): array {
 		$result = $query->executeQuery();
 		$data = [];
 		while ($row = $result->fetch()) {
-			$data[$row['share_with']] = $row['count'];
+			$data[$row['share_with']] = (int)$row['count'];
 		}
+
 		$result->closeCursor();
 
 		return $data;
 	}
 
+	/**
+	 * @return array{shares: list<array{
+	 *     id: string,
+	 *     shared_by: string,
+	 *     mime_type: int,
+	 *     name: string,
+	 *     time: int,
+	 * }>}
+	 */
 	public function getGuestInfo(string $userId): array {
 		$shares = array_merge(
 			$this->shareManager->getSharedWith($userId, IShare::TYPE_USER, null, -1, 0),
diff --git a/lib/Hooks.php b/lib/Hooks.php
index 69c3fd5b3..0005be3bf 100644
--- a/lib/Hooks.php
+++ b/lib/Hooks.php
@@ -17,7 +17,6 @@
 use OCP\Constants;
 use OCP\Files\Storage\IStorage;
 use OCP\IConfig;
-use OCP\IUser;
 use OCP\IUserManager;
 use OCP\IUserSession;
 use OCP\Share\Events\ShareCreatedEvent;
@@ -45,7 +44,7 @@ public function handlePostShare(ShareCreatedEvent $event): void {
 
 		if (!$isGuest) {
 			$this->logger->debug(
-				"ignoring user '$shareWith', not a guest",
+				"ignoring user '" . $shareWith . "', not a guest",
 				['app' => Application::APP_ID]
 			);
 			return;
@@ -69,7 +68,7 @@ public function handlePostShare(ShareCreatedEvent $event): void {
 			);
 		}
 
-		$this->logger->debug("checking if '$shareWith' has a password",
+		$this->logger->debug("checking if '" . $shareWith . "' has a password",
 			['app' => Application::APP_ID]);
 
 		$uid = $user->getUID();
@@ -77,19 +76,23 @@ public function handlePostShare(ShareCreatedEvent $event): void {
 		$this->inviteService->sendInvite($uid, $shareWith, $share);
 	}
 
+	/**
+	 * @param array<string, mixed> $params
+	 */
 	public function setupReadonlyFilesystem(array $params): void {
 		$uid = $params['user'];
 		$user = $this->userManager->get($uid);
 
 		if ($user && $this->guestManager->isGuest($user)) {
 			Filesystem::addStorageWrapper('guests.readonly', function ($mountPoint, IStorage $storage) use ($uid): ReadOnlyJail|IStorage {
-				if ($mountPoint === "/$uid/") {
+				if ($mountPoint === sprintf('/%s/', $uid)) {
 					return new ReadOnlyJail([
 						'storage' => $storage,
 						'mask' => Constants::PERMISSION_READ,
 						'path' => 'files'
 					]);
 				}
+
 				return $storage;
 			});
 		}
@@ -100,7 +103,6 @@ public function handleFirstLogin(UserFirstTimeLoggedInEvent $event): void {
 			return;
 		}
 
-		/** @var IUser $user */
 		$user = $event->getUser();
 		$this->logger->debug('User ' . $user->getUID() . ' logged in for the very first time. Checking guests data import.');
 
@@ -115,14 +117,14 @@ public function handleFirstLogin(UserFirstTimeLoggedInEvent $event): void {
 			return;
 		}
 
-		if (strtolower($email) === strtolower((string)$user->getUID())) {
+		if (strtolower($email) === strtolower($user->getUID())) {
 			// This is the guest user, logging in for the very first time
 			return;
 		}
 
 		$guestUser = $this->userManager->get($email);
 		if ($guestUser === null) {
-			$this->logger->warning("Guest user $email does not exist (anymore)");
+			$this->logger->warning('Guest user ' . $email . ' does not exist (anymore)');
 			return;
 		}
 
diff --git a/lib/Listener/BeforeTemplateRenderedListener.php b/lib/Listener/BeforeTemplateRenderedListener.php
index 46d63f28b..5ea01f575 100644
--- a/lib/Listener/BeforeTemplateRenderedListener.php
+++ b/lib/Listener/BeforeTemplateRenderedListener.php
@@ -36,6 +36,7 @@ public function handle(Event $event): void {
 		if (!$this->config->canCreateGuests()) {
 			return;
 		}
+
 		Util::addScript('guests', 'guests-init');
 		Util::addScript('guests', 'guests-contactsmenu');
 
diff --git a/lib/Mail.php b/lib/Mail.php
index e9335e424..ead0be5b3 100644
--- a/lib/Mail.php
+++ b/lib/Mail.php
@@ -16,6 +16,7 @@
 use OCP\IUserManager;
 use OCP\IUserSession;
 use OCP\L10N\IFactory;
+use OCP\Mail\IEMailTemplate;
 use OCP\Mail\IMailer;
 use OCP\Share\IShare;
 use OCP\Util;
@@ -42,6 +43,7 @@ public function sendGuestInviteMail(string $uid, string $guest, string $token, s
 		if ($language === '') {
 			$language = null;
 		}
+
 		$l10n = $this->l10nFactory->get('guests', $language);
 
 		$passwordLink = $this->urlGenerator->linkToRouteAbsolute(
@@ -54,6 +56,7 @@ public function sendGuestInviteMail(string $uid, string $guest, string $token, s
 		if (!$guestEmail) {
 			throw new \Exception('Guest user created without email');
 		}
+
 		$replyTo = $this->userManager->get($uid)->getEMailAddress();
 		$senderDisplayName = $this->userSession->getUser()->getDisplayName();
 
@@ -84,11 +87,14 @@ public function sendGuestInviteMail(string $uid, string $guest, string $token, s
 			$this->mailer->send($message);
 		} catch (\Exception) {
 			throw new \Exception($l10n->t(
-				'Couldn\'t send reset email. Please contact your administrator.'
+				"Couldn't send reset email. Please contact your administrator."
 			));
 		}
 	}
 
+	/**
+	 * @return array{string, IEMailTemplate}
+	 */
 	private function composeShareMessage(IShare $share, string $senderDisplayName, string $guestEmail, string $passwordLink, IL10N $l10n): array {
 		$filename = trim($share->getTarget(), '/');
 		$subject = $l10n->t('%s shared a file with you', [$senderDisplayName]);
@@ -135,6 +141,9 @@ private function composeShareMessage(IShare $share, string $senderDisplayName, s
 		return [ $subject, $emailTemplate ];
 	}
 
+	/**
+	 * @return array{string, IEMailTemplate}
+	 */
 	private function composeInviteMessage(string $senderDisplayName, string $guestEmail, string $passwordLink, IL10N $l10n): array {
 		$subject = $l10n->t('%s invited you as a guest', [$senderDisplayName]);
 
diff --git a/lib/Migration/OwncloudGuestsMigration.php b/lib/Migration/OwncloudGuestsMigration.php
index 9b807300a..21063c309 100644
--- a/lib/Migration/OwncloudGuestsMigration.php
+++ b/lib/Migration/OwncloudGuestsMigration.php
@@ -36,9 +36,9 @@ public function run(IOutput $output): void {
 		if (!$this->shouldRun()) {
 			$this->logger->info('Skipping owncloud guests migration, no owncloud guests found');
 			return;
-		} else {
-			$this->runStep($output);
 		}
+
+		$this->runStep($output);
 	}
 
 	protected function shouldRun(): bool {
@@ -48,7 +48,7 @@ protected function shouldRun(): bool {
 			return false;
 		}
 
-		$this->logger->info("Found $count owncloud guests to migrate");
+		$this->logger->info('Found ' . $count . ' owncloud guests to migrate');
 
 		return true;
 	}
@@ -79,14 +79,15 @@ protected function runStep(IOutput $output): void {
 					if ($guestUser) {
 						$guestUser->setQuota('0 B');
 					} else {
-						$output->warning("Could not set quota for guest $userID");
+						$output->warning('Could not set quota for guest ' . $userID);
 					}
 				} else {
-					$output->warning("Could not get hashed password for guest $userID, skipping");
+					$output->warning('Could not get hashed password for guest ' . $userID . ', skipping');
 				}
 			} else {
-				$output->warning("Failed to get user data for guest $userID, skipping");
+				$output->warning('Failed to get user data for guest ' . $userID . ', skipping');
 			}
+
 			$output->advance();
 		}
 	}
diff --git a/lib/Migration/Version1Date20180615130406.php b/lib/Migration/Version1Date20180615130406.php
index 3542d3aca..24fc75f25 100644
--- a/lib/Migration/Version1Date20180615130406.php
+++ b/lib/Migration/Version1Date20180615130406.php
@@ -1,10 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * SPDX-FileCopyrightText: 2018 Nextcloud GmbH and Nextcloud contributors
  * SPDX-License-Identifier: AGPL-3.0-or-later
  */
-
 namespace OCA\Guests\Migration;
 
 use OCP\DB\ISchemaWrapper;
diff --git a/lib/Notifications/Notifier.php b/lib/Notifications/Notifier.php
index eea72f889..4000dc7e5 100644
--- a/lib/Notifications/Notifier.php
+++ b/lib/Notifications/Notifier.php
@@ -33,6 +33,9 @@ public function getName(): string {
 		return $this->factory->get(Application::APP_ID)->t('Guests');
 	}
 
+	/**
+	 * @return array<string, array<string, mixed>>
+	 */
 	private function getRichMessageParams(string $source, string $target): array {
 		$sourceUser = $this->userManager->get($source);
 		$targetUser = $this->userManager->get($target);
diff --git a/lib/RestrictionManager.php b/lib/RestrictionManager.php
index c67323726..e4a68f6d0 100644
--- a/lib/RestrictionManager.php
+++ b/lib/RestrictionManager.php
@@ -70,22 +70,17 @@ public function setupRestrictions(): void {
 	}
 
 	public function lateSetupRestrictions(): void {
-		if ($this->guestManager->isGuest($this->userSession->getUser())) {
-			if ($this->config->hideOtherUsers()) {
-				$this->server->getContactsManager()->clear();
-
-				$this->userBackend->setAllowListing(false);
-
-				/** @var AppConfigOverwrite $appConfig */
-				$appConfig = $this->server->get(AppConfigOverwrite::class);
-				$appConfig->setOverwrite([
-					'core' => [
-						'shareapi_only_share_with_group_members' => 'yes'
-					]
-				]);
-
-				$this->server->registerService(AppConfig::class, fn () => $appConfig);
-			}
+		if ($this->guestManager->isGuest($this->userSession->getUser()) && $this->config->hideOtherUsers()) {
+			$this->server->getContactsManager()->clear();
+			$this->userBackend->setAllowListing(false);
+			/** @var AppConfigOverwrite $appConfig */
+			$appConfig = $this->server->get(AppConfigOverwrite::class);
+			$appConfig->setOverwrite([
+				'core' => [
+					'shareapi_only_share_with_group_members' => 'yes'
+				]
+			]);
+			$this->server->registerService(AppConfig::class, fn () => $appConfig);
 		}
 	}
 }
diff --git a/lib/Service/InviteService.php b/lib/Service/InviteService.php
index 1316a02ac..588046894 100644
--- a/lib/Service/InviteService.php
+++ b/lib/Service/InviteService.php
@@ -46,11 +46,11 @@ public function sendInvite(string $userId, string $guest, ?IShare $share = null)
 				$share
 			);
 
-			if ($share) {
+			if ($share instanceof IShare) {
 				$share->setMailSend(false);
 			}
 		} catch (DoesNotExistException) {
-			$this->logger->error("'$guest' does not exist");
+			$this->logger->error('"' . $guest . '" does not exist');
 		} catch (\Exception $e) {
 			$this->logger->error('Failed to send guest activation mail', ['exception' => $e]);
 		}
diff --git a/lib/Storage/DirMask.php b/lib/Storage/DirMask.php
index a6bd3c9a9..125511819 100644
--- a/lib/Storage/DirMask.php
+++ b/lib/Storage/DirMask.php
@@ -25,6 +25,7 @@ class DirMask extends PermissionsMask {
 	 * @var string the dir that should be masked
 	 */
 	private readonly string $path;
+
 	/**
 	 * @var int remember length
 	 */
@@ -91,6 +92,7 @@ public function rename($source, $target): bool {
 		if (!$this->isUpdatable($source)) {
 			return false;
 		}
+
 		if ($this->file_exists($target)) {
 			if ($this->isUpdatable($target)) {
 				return $this->storage->rename($source, $target);
@@ -100,10 +102,12 @@ public function rename($source, $target): bool {
 			if ($parent === '.') {
 				$parent = '';
 			}
+
 			if ($this->isCreatable($parent)) {
 				return $this->storage->rename($source, $target);
 			}
 		}
+
 		return false;
 	}
 
@@ -111,6 +115,7 @@ public function copy($source, $target): bool {
 		if (!$this->isReadable($source)) {
 			return false;
 		}
+
 		if ($this->file_exists($target)) {
 			if ($this->isUpdatable($target)) {
 				return $this->storage->copy($source, $target);
@@ -120,10 +125,12 @@ public function copy($source, $target): bool {
 			if ($parent === '.') {
 				$parent = '';
 			}
+
 			if ($this->isCreatable($parent)) {
 				return $this->storage->copy($source, $target);
 			}
 		}
+
 		return false;
 	}
 
@@ -180,6 +187,7 @@ public function getCache($path = '', $storage = null): ICache {
 		if (!$storage) {
 			$storage = $this;
 		}
+
 		$sourceCache = $this->storage->getCache($path, $storage);
 		return new DirMaskCache($sourceCache, $this->mask, $this->checkPath(...));
 	}
diff --git a/lib/TransferService.php b/lib/TransferService.php
index 178d92774..3451319c7 100644
--- a/lib/TransferService.php
+++ b/lib/TransferService.php
@@ -39,11 +39,11 @@ public function transfer(IUser $guestUser, IUser $user): void {
 		try {
 			/** @var OwnershipTransferService $ownershipTransferService */
 			$ownershipTransferService = $this->container->get(OwnershipTransferService::class);
-		} catch (QueryException $e) {
+		} catch (QueryException $queryException) {
 			$this->logger->error('Could not resolve ownership transfer service to import guest user data', [
-				'exception' => $e,
+				'exception' => $queryException,
 			]);
-			throw $e;
+			throw $queryException;
 		}
 
 		try {
@@ -55,11 +55,11 @@ public function transfer(IUser $guestUser, IUser $user): void {
 				true,
 				true
 			);
-		} catch (TransferOwnershipException $e) {
+		} catch (TransferOwnershipException $transferOwnershipException) {
 			$this->logger->error('Could not import guest user data', [
-				'exception' => $e,
+				'exception' => $transferOwnershipException,
 			]);
-			throw $e;
+			throw $transferOwnershipException;
 		}
 
 		// Update incomming shares
diff --git a/lib/UserBackend.php b/lib/UserBackend.php
index 4a34f56c3..e5e0a9306 100644
--- a/lib/UserBackend.php
+++ b/lib/UserBackend.php
@@ -39,6 +39,7 @@ class UserBackend extends ABackend implements
 	IPasswordHashBackend {
 
 	private CappedMemoryCache $cache;
+
 	private bool $allowListing = true;
 
 	public function __construct(
@@ -75,7 +76,7 @@ public function createUser(string $uid, string $password): bool {
 			// Clear cache
 			unset($this->cache[$uid]);
 
-			return $result ? true : false;
+			return (bool)$result;
 		}
 
 		return false;
@@ -99,7 +100,7 @@ public function deleteUser($uid): bool {
 			unset($this->cache[$uid]);
 		}
 
-		return $result ? true : false;
+		return (bool)$result;
 	}
 
 	/**
@@ -117,7 +118,7 @@ public function setPassword(string $uid, string $password): bool {
 				->where($query->expr()->eq('uid_lower', $query->createNamedParameter(mb_strtolower($uid))));
 			$result = $query->executeStatement();
 
-			return $result ? true : false;
+			return (bool)$result;
 		}
 
 		return false;
@@ -127,6 +128,7 @@ public function getPasswordHash(string $userId): ?string {
 		if (!$this->userExists($userId)) {
 			return null;
 		}
+
 		$qb = $this->dbConn->getQueryBuilder();
 		$qb->select('password')
 			->from('guests_users')
@@ -136,6 +138,7 @@ public function getPasswordHash(string $userId): ?string {
 		if ($hash === false) {
 			return null;
 		}
+
 		return $hash;
 	}
 
@@ -143,6 +146,7 @@ public function setPasswordHash(string $userId, string $passwordHash): bool {
 		if (!$this->hasher->validate($passwordHash)) {
 			throw new InvalidArgumentException();
 		}
+
 		$qb = $this->dbConn->getQueryBuilder();
 		$qb->update('guests_users')
 			->set('password', $qb->createNamedParameter($passwordHash))
@@ -191,41 +195,40 @@ public function getDisplayName($uid): string {
 	public function getDisplayNames($search = '', $limit = null, $offset = null): array {
 		if (!$this->allowListing) {
 			return [];
-		} else {
-			$query = $this->dbConn->getQueryBuilder();
-
-			if ($search === '') {
-				$query->select('uid', 'displayname')
-					->from('guests_users', 'u')
-					->orderBy('uid_lower', 'ASC')
-					->setMaxResults($limit)
-					->setFirstResult($offset);
-			} else {
-				$query->select('uid', 'displayname')
-					->from('guests_users', 'u')
-					->leftJoin('u', 'preferences', 'p', $query->expr()->andX(
-						$query->expr()->eq('userid', 'uid'),
-						$query->expr()->eq('appid', $query->expr()->literal('settings')),
-						$query->expr()->eq('configkey', $query->expr()->literal('email')))
-					)
-					// sqlite doesn't like re-using a single named parameter here
-					->where($query->expr()->iLike('uid', $query->createPositionalParameter('%' . $this->dbConn->escapeLikeParameter($search) . '%')))
-					->orWhere($query->expr()->iLike('displayname', $query->createPositionalParameter('%' . $this->dbConn->escapeLikeParameter($search) . '%')))
-					->orWhere($query->expr()->iLike('configvalue', $query->createPositionalParameter('%' . $this->dbConn->escapeLikeParameter($search) . '%')))
-					->orderBy($query->func()->lower('displayname'), 'ASC')
-					->orderBy('uid_lower', 'ASC')
-					->setMaxResults($limit)
-					->setFirstResult($offset);
-			}
+		}
 
-			$result = $query->executeQuery();
-			$displayNames = [];
-			while ($row = $result->fetch()) {
-				$displayNames[(string)$row['uid']] = (string)$row['displayname'];
-			}
+		$query = $this->dbConn->getQueryBuilder();
+		if ($search === '') {
+			$query->select('uid', 'displayname')
+				->from('guests_users', 'u')
+				->orderBy('uid_lower', 'ASC')
+				->setMaxResults($limit)
+				->setFirstResult($offset);
+		} else {
+			$query->select('uid', 'displayname')
+				->from('guests_users', 'u')
+				->leftJoin('u', 'preferences', 'p', $query->expr()->andX(
+					$query->expr()->eq('userid', 'uid'),
+					$query->expr()->eq('appid', $query->expr()->literal('settings')),
+					$query->expr()->eq('configkey', $query->expr()->literal('email')))
+				)
+				// sqlite doesn't like re-using a single named parameter here
+				->where($query->expr()->iLike('uid', $query->createPositionalParameter('%' . $this->dbConn->escapeLikeParameter($search) . '%')))
+				->orWhere($query->expr()->iLike('displayname', $query->createPositionalParameter('%' . $this->dbConn->escapeLikeParameter($search) . '%')))
+				->orWhere($query->expr()->iLike('configvalue', $query->createPositionalParameter('%' . $this->dbConn->escapeLikeParameter($search) . '%')))
+				->orderBy($query->func()->lower('displayname'), 'ASC')
+				->orderBy('uid_lower', 'ASC')
+				->setMaxResults($limit)
+				->setFirstResult($offset);
+		}
 
-			return $displayNames;
+		$result = $query->executeQuery();
+		$displayNames = [];
+		while ($row = $result->fetch()) {
+			$displayNames[(string)$row['uid']] = (string)$row['displayname'];
 		}
+
+		return $displayNames;
 	}
 
 	/**
@@ -255,9 +258,10 @@ public function checkPassword(string $loginName, string $password) {
 			$storedHash = $row['password'];
 			$newHash = '';
 			if ($this->hasher->verify($password, $storedHash, $newHash)) {
-				if (!empty($newHash)) {
+				if ($newHash !== '') {
 					$this->setPassword($loginName, $password);
 				}
+
 				return (string)$row['uid'];
 			}
 		}
diff --git a/rector.php b/rector.php
index bd8e90773..f1c95c239 100644
--- a/rector.php
+++ b/rector.php
@@ -9,6 +9,7 @@
 use Rector\Config\RectorConfig;
 use Rector\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector;
 use Rector\PHPUnit\Set\PHPUnitSetList;
+use Rector\TypeDeclaration\Rector\StmtsAwareInterface\SafeDeclareStrictTypesRector;
 
 return RectorConfig::configure()
 	->withPaths([
@@ -23,7 +24,18 @@
 	)
 	->withPreparedSets(
 		deadCode: true,
+		codeQuality: true,
+		codingStyle: true,
 		typeDeclarations: true,
+		typeDeclarationDocblocks: true,
+		privatization: true,
+		instanceOf: true,
+		earlyReturn: true,
+		rectorPreset: true,
+		phpunitCodeQuality: true,
+		doctrineCodeQuality: true,
+		symfonyCodeQuality: true,
+		symfonyConfigs: true,
 	)->withPhpSets(
 		php81: true,
 	)->withConfiguredRule(ClassPropertyAssignToConstructorPromotionRector::class, [
@@ -33,4 +45,7 @@
 	->withSets([
 		NextcloudSets::NEXTCLOUD_30,
 		PHPUnitSetList::PHPUNIT_100,
+	])
+	->withRules([
+		SafeDeclareStrictTypesRector::class,
 	]);
diff --git a/tests/integration/features/bootstrap/GuestsContext.php b/tests/integration/features/bootstrap/GuestsContext.php
index b2f2442b2..4a31a2f72 100644
--- a/tests/integration/features/bootstrap/GuestsContext.php
+++ b/tests/integration/features/bootstrap/GuestsContext.php
@@ -18,6 +18,10 @@
  * Guests context.
  */
 class GuestsContext implements Context, SnippetAcceptingContext {
+	public $baseUrl;
+
+	public $response;
+
 	use Webdav;
 
 	private array $createdGuests = [];
@@ -32,26 +36,23 @@ public function prepareUserNameAsFrontend(string $guestDisplayName, $guestEmail)
 	 * @param string $user
 	 */
 	public function userCreatedAGuestUser($user, string $guestDisplayName, string $guestEmail): void {
-		$fullUrl = substr($this->baseUrl, 0, -4) . '/index.php/apps/guests/users';
+		$fullUrl = substr((string)$this->baseUrl, 0, -4) . '/index.php/apps/guests/users';
 		//Replicating frontend behaviour
 		$userName = $this->prepareUserNameAsFrontend($guestDisplayName, $guestEmail);
 		$fullUrl = $fullUrl . '?displayName=' . $guestDisplayName . '&email=' . $guestEmail . '&username=' . $userName;
 		$client = new Client();
 		$options = [];
-		if ($user === 'admin') {
-			$options['auth'] = $this->adminUser;
-		} else {
-			$options['auth'] = [$user, $this->regularUser];
-		}
+		$options['auth'] = $user === 'admin' ? $this->adminUser : [$user, $this->regularUser];
 		$request = $client->createRequest('PUT', $fullUrl, $options);
 		$request->addHeader('Content-Type', 'application/x-www-form-urlencoded');
 
 		try {
 			$this->response = $client->send($request);
-		} catch (BadResponseException $e) {
+		} catch (BadResponseException $badResponseException) {
 			// 4xx and 5xx responses cause an exception
-			$this->response = $e->getResponse();
+			$this->response = $badResponseException->getResponse();
 		}
+
 		$this->createdGuests[$guestDisplayName] = $guestEmail;
 	}
 
@@ -110,8 +111,8 @@ public function guestUserSetsItsPassword(string $guestDisplayName): void {
 		];
 		try {
 			$this->response = $client->send($client->createRequest('POST', $urlSetPasswd, $options));
-		} catch (ClientException $ex) {
-			$this->response = $ex->getResponse();
+		} catch (ClientException $clientException) {
+			$this->response = $clientException->getResponse();
 		}
 	}
 
@@ -120,7 +121,7 @@ public function guestUserSetsItsPassword(string $guestDisplayName): void {
 	 * @AfterScenario
 	 */
 	public function cleanupGuests(): void {
-		foreach ($this->createdGuests as $displayName => $email) {
+		foreach (array_keys($this->createdGuests) as $displayName) {
 			$this->deleteGuestUser($displayName);
 		}
 	}
diff --git a/tests/unit/AppWhitelistTest.php b/tests/unit/AppWhitelistTest.php
index 2dcb32e3a..378fec800 100644
--- a/tests/unit/AppWhitelistTest.php
+++ b/tests/unit/AppWhitelistTest.php
@@ -21,9 +21,13 @@
 
 class AppWhitelistTest extends TestCase {
 	private Config&MockObject $config;
+
 	private GuestManager&MockObject $guestManager;
+
 	private IL10N&MockObject $l10n;
+
 	private IAppManager&MockObject $appManager;
+
 	private IURLGenerator&MockObject $urlGenerator;
 
 	private ?AppWhitelist $appWhitelist = null;
@@ -56,7 +60,7 @@ public function testIsUrlAllowed(): void {
 			->willReturn(true);
 		$this->guestManager->method('isGuest')
 			->willReturn(true);
-		$user = $this->createMock(IUser::class);
+		$user = $this->createStub(IUser::class);
 
 		$this->assertFalse($this->appWhitelist->isUrlAllowed($user, '/apps/news/...'));
 		$this->assertTrue($this->appWhitelist->isUrlAllowed($user, '/apps/foo/...'));
@@ -69,7 +73,7 @@ public function testIsUrlAllowedNoWhitelist(): void {
 			->willReturn(false);
 		$this->guestManager->method('isGuest')
 			->willReturn(true);
-		$user = $this->createMock(IUser::class);
+		$user = $this->createStub(IUser::class);
 
 		$this->assertTrue($this->appWhitelist->isUrlAllowed($user, '/apps/news/...'));
 		$this->assertTrue($this->appWhitelist->isUrlAllowed($user, '/apps/foo/...'));
diff --git a/tests/unit/Command/AddCommandTest.php b/tests/unit/Command/AddCommandTest.php
index 70c716d11..c3fad58da 100644
--- a/tests/unit/Command/AddCommandTest.php
+++ b/tests/unit/Command/AddCommandTest.php
@@ -21,11 +21,15 @@
 class AddCommandTest extends TestCase {
 	/** @var IUserManager|MockObject */
 	private $userManager;
+
 	/** @var GuestManager|MockObject */
 	private $guestManager;
+
 	/** @var IMailer|MockObject */
 	private $mailer;
+
 	private ?AddCommand $command = null;
+
 	private ?CommandTester $commandTester = null;
 
 	protected function setUp(): void {
@@ -41,9 +45,13 @@ protected function setUp(): void {
 			$this->guestManager
 		);
 		$this->command->setApplication(new Application());
+
 		$this->commandTester = new CommandTester($this->command);
 	}
 
+	/**
+	 * @return array<int, array<int, array<string, string>>|array<int, array<string, bool|string>>>
+	 */
 	public function createGuestDataProvider() {
 		return [
 			[
@@ -68,7 +76,7 @@ public function createGuestDataProvider() {
 	 * @dataProvider createGuestDataProvider
 	 */
 	public function testCreateGuest($commandArgs): void {
-		$createdByUser = $this->createMock(IUser::class);
+		$createdByUser = $this->createStub(IUser::class);
 
 		$password = 'guest-password';
 		if (isset($commandArgs['--generate-password'])) {
@@ -107,6 +115,7 @@ public function testCreateGuest($commandArgs): void {
 
 		$this->commandTester->setInputs(['guest-password', 'guest-password']);
 		$this->commandTester->execute($commandArgs);
+
 		$output = $this->commandTester->getDisplay();
 		$this->assertStringContainsString('The guest account user "guestid" was created successfully', $output);
 	}
diff --git a/tests/unit/ConfigTest.php b/tests/unit/ConfigTest.php
index 797a52456..6180bd149 100644
--- a/tests/unit/ConfigTest.php
+++ b/tests/unit/ConfigTest.php
@@ -23,12 +23,16 @@
 class ConfigTest extends TestCase {
 	/** @var IConfig|MockObject */
 	private $config;
+
 	/** @var IAppConfig|MockObject */
 	private $appConfig;
+
 	/** @var ISubAdmin|MockObject */
 	private $subAdmin;
+
 	/** @var IUserSession|MockObject */
 	private $userSession;
+
 	/** @var IGroupManager|MockObject */
 	private $groupManager;
 
@@ -152,7 +156,7 @@ public function testCanCreateGuestsNoUser(): void {
 	}
 
 	public function testCanCreateGuestsWithGroupRestrictionNoMatch(): void {
-		$user = $this->createMock(IUser::class);
+		$user = $this->createStub(IUser::class);
 		$this->userSession->method('getUser')
 			->willReturn($user);
 
@@ -168,7 +172,7 @@ public function testCanCreateGuestsWithGroupRestrictionNoMatch(): void {
 	}
 
 	public function testCanCreateGuestsWithGroupRestrictionWithMatch(): void {
-		$user = $this->createMock(IUser::class);
+		$user = $this->createStub(IUser::class);
 		$this->userSession->method('getUser')
 			->willReturn($user);
 
@@ -188,7 +192,7 @@ public function testCanCreateGuestsWithGroupRestrictionWithMatch(): void {
 	}
 
 	public function testCanCreateGuestsWithSharingRestrictedButIsSubAdmin(): void {
-		$user = $this->createMock(IUser::class);
+		$user = $this->createStub(IUser::class);
 		$this->userSession->method('getUser')
 			->willReturn($user);
 
@@ -208,7 +212,7 @@ public function testCanCreateGuestsWithSharingRestrictedButIsSubAdmin(): void {
 	}
 
 	public function testCanCreateGuestsWithSharingRestrictedNotSubAdmin(): void {
-		$user = $this->createMock(IUser::class);
+		$user = $this->createStub(IUser::class);
 		$this->userSession->method('getUser')
 			->willReturn($user);
 
diff --git a/tests/unit/Controller/UsersControllerTest.php b/tests/unit/Controller/UsersControllerTest.php
index b6858a198..fc5d155d8 100644
--- a/tests/unit/Controller/UsersControllerTest.php
+++ b/tests/unit/Controller/UsersControllerTest.php
@@ -32,19 +32,33 @@
 
 class UsersControllerTest extends TestCase {
 	private IRequest&MockObject $request;
+
 	private IUserManager&MockObject $userManager;
+
 	private IL10N&MockObject $l10n;
+
 	private Config $guestsConfig;
+
 	private IMailer&MockObject $mailer;
+
 	private GuestManager&MockObject $guestManager;
+
 	private IUserSession&MockObject $userSession;
+
 	private ISubAdmin&MockObject $subAdmin;
+
 	private IGroupManager&MockObject $groupManager;
+
 	private TransferService&MockObject $transferService;
+
 	private TransferMapper&MockObject $transferMapper;
+
 	private IAppConfig&MockObject $appConfig;
+
 	private IConfig&MockObject $config;
+
 	private InviteService&MockObject $inviteService;
+
 	private UsersController $controller;
 
 	protected function setUp(): void {
@@ -96,7 +110,7 @@ protected function setUp(): void {
 	 * Test that creation fails when the current user is a guest.
 	 */
 	public function testCreateWhenCurrentUserIsGuest(): void {
-		$currentUser = $this->createMock(IUser::class);
+		$currentUser = $this->createStub(IUser::class);
 		$this->userSession->method('getUser')
 			->willReturn($currentUser);
 
@@ -200,7 +214,7 @@ public function testCreateSucceedsForAdminDespiteGroupRestrictions(): void {
 		$this->userManager->method('userExists')
 			->willReturn(false);
 
-		$guestUser = $this->createMock(IUser::class);
+		$guestUser = $this->createStub(IUser::class);
 		$this->guestManager->method('createGuest')
 			->willReturn($guestUser);
 
@@ -247,7 +261,7 @@ public function testCreateSucceedsWhenUserInAllowedGroup(): void {
 		$this->userManager->method('userExists')
 			->willReturn(false);
 
-		$guestUser = $this->createMock(IUser::class);
+		$guestUser = $this->createStub(IUser::class);
 		$this->guestManager->method('createGuest')
 			->willReturn($guestUser);
 
@@ -309,7 +323,7 @@ public function testCreateSucceedsForSubAdminWhenSharingIsRestricted(): void {
 		$this->userManager->method('userExists')
 			->willReturn(false);
 
-		$guestUser = $this->createMock(IUser::class);
+		$guestUser = $this->createStub(IUser::class);
 		$this->guestManager->method('createGuest')
 			->willReturn($guestUser);
 
@@ -395,7 +409,7 @@ public function testCreateSucceedsWhenNoRestrictions(): void {
 		$this->userManager->method('userExists')
 			->willReturn(false);
 
-		$guestUser = $this->createMock(IUser::class);
+		$guestUser = $this->createStub(IUser::class);
 		$this->guestManager->method('createGuest')
 			->willReturn($guestUser);
 
@@ -495,7 +509,7 @@ public function testCreateWithGroupButNotSubAdmin(): void {
 			->with($currentUser)
 			->willReturn(false);
 
-		$group = $this->createMock(IGroup::class);
+		$group = $this->createStub(IGroup::class);
 		$this->groupManager->method('get')
 			->with('testgroup')
 			->willReturn($group);
@@ -577,7 +591,7 @@ public function testCreateWithExistingEmailUser(): void {
 			->with('existing@example.com')
 			->willReturn(true);
 
-		$existingUser = $this->createMock(IUser::class);
+		$existingUser = $this->createStub(IUser::class);
 		$this->userManager->method('getByEmail')
 			->with('existing@example.com')
 			->willReturn([$existingUser]);
@@ -641,7 +655,7 @@ public function testCreateSuccessWithGroupsAsSubadmin(): void {
 
 		$group1 = $this->createMock(IGroup::class);
 		$group2 = $this->createMock(IGroup::class);
-		$this->groupManager->method('get')
+		$this->groupManager->expects($this->exactly(2))->method('get')
 			->willReturnMap([
 				['group1', $group1],
 				['group2', $group2],
@@ -668,7 +682,7 @@ public function testCreateSuccessWithGroupsAsSubadmin(): void {
 			->with('new@example.com')
 			->willReturn(false);
 
-		$guestUser = $this->createMock(IUser::class);
+		$guestUser = $this->createStub(IUser::class);
 		$this->userManager->method('get')
 			->with('new@example.com')
 			->willReturn($guestUser);
diff --git a/tests/unit/GroupBackendTest.php b/tests/unit/GroupBackendTest.php
index c364b2d3b..2fbfcc5fc 100644
--- a/tests/unit/GroupBackendTest.php
+++ b/tests/unit/GroupBackendTest.php
@@ -19,8 +19,10 @@
 class GroupBackendTest extends TestCase {
 	/** @var GuestManager|MockObject */
 	private $guestManager;
+
 	/** @var Config|MockObject */
 	private $config;
+
 	/** @var IUserSession|MockObject */
 	private $userSession;
 
@@ -49,6 +51,9 @@ private function setUID(string $uid): void {
 			->willReturn($user);
 	}
 
+	/**
+	 * @param string[] $uids
+	 */
 	private function setGuests(array $uids): void {
 		$this->guestManager->method('listGuests')
 			->willReturn($uids);
diff --git a/tests/unit/GuestManagerTest.php b/tests/unit/GuestManagerTest.php
index bdd5c45f5..0dc1f59e9 100644
--- a/tests/unit/GuestManagerTest.php
+++ b/tests/unit/GuestManagerTest.php
@@ -25,20 +25,28 @@
 class GuestManagerTest extends TestCase {
 	/** @var UserBackend|MockObject */
 	private $userBackend;
+
 	/** @var IUserSession|MockObject */
 	private $userSession;
+
 	/** @var IUserManager|MockObject */
 	private $userManager;
+
 	/** @var IConfig|MockObject */
 	private $config;
+
 	/** @var ISecureRandom|MockObject */
 	private $random;
+
 	/** @var ICrypto|MockObject */
 	private $crypto;
+
 	/** @var IManager|MockObject */
 	private $shareManager;
+
 	/** @var IDBConnection|MockObject */
 	private $conneciton;
+
 	/** @var IEventDispatcher|MockObject */
 	private $eventDispatcher;
 
@@ -131,6 +139,7 @@ public function testCreateGuest(): void {
 				if (!isset($setValues[$app])) {
 					$setValues[$app] = [];
 				}
+
 				$setValues[$app][$key] = $value;
 			});
 
diff --git a/tests/unit/Migration/OwncloudGuestMigrationTest.php b/tests/unit/Migration/OwncloudGuestMigrationTest.php
index a50ba9be7..9e742cc17 100644
--- a/tests/unit/Migration/OwncloudGuestMigrationTest.php
+++ b/tests/unit/Migration/OwncloudGuestMigrationTest.php
@@ -25,9 +25,13 @@
  */
 class OwncloudGuestMigrationTest extends TestCase {
 	private IConfig $config;
+
 	private IUserManager $userManager;
+
 	private BufferedOutput $consoleOutput;
+
 	private ConsoleOutput $migrationOutput;
+
 	private GuestManager $guestManager;
 
 	protected function setUp():void {
diff --git a/vendor-bin/rector/composer.lock b/vendor-bin/rector/composer.lock
index 5f6b688f7..d053cd497 100644
--- a/vendor-bin/rector/composer.lock
+++ b/vendor-bin/rector/composer.lock
@@ -122,11 +122,11 @@
         },
         {
             "name": "phpstan/phpstan",
-            "version": "2.1.36",
+            "version": "2.1.38",
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/2132e5e2361d11d40af4c17faa16f043269a4cf3",
-                "reference": "2132e5e2361d11d40af4c17faa16f043269a4cf3",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/dfaf1f530e1663aa167bc3e52197adb221582629",
+                "reference": "dfaf1f530e1663aa167bc3e52197adb221582629",
                 "shasum": ""
             },
             "require": {
@@ -171,7 +171,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2026-01-21T13:58:26+00:00"
+            "time": "2026-01-30T17:12:46+00:00"
         },
         {
             "name": "psr/clock",
@@ -376,21 +376,21 @@
         },
         {
             "name": "rector/rector",
-            "version": "2.3.4",
+            "version": "2.3.6",
             "source": {
                 "type": "git",
                 "url": "https://github.com/rectorphp/rector.git",
-                "reference": "9227d7a24b0f23ae941057509364f948d5da9ab2"
+                "reference": "ca9ebb81d280cd362ea39474dabd42679e32ca6b"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/rectorphp/rector/zipball/9227d7a24b0f23ae941057509364f948d5da9ab2",
-                "reference": "9227d7a24b0f23ae941057509364f948d5da9ab2",
+                "url": "https://api.github.com/repos/rectorphp/rector/zipball/ca9ebb81d280cd362ea39474dabd42679e32ca6b",
+                "reference": "ca9ebb81d280cd362ea39474dabd42679e32ca6b",
                 "shasum": ""
             },
             "require": {
                 "php": "^7.4|^8.0",
-                "phpstan/phpstan": "^2.1.36"
+                "phpstan/phpstan": "^2.1.38"
             },
             "conflict": {
                 "rector/rector-doctrine": "*",
@@ -424,7 +424,7 @@
             ],
             "support": {
                 "issues": "https://github.com/rectorphp/rector/issues",
-                "source": "https://github.com/rectorphp/rector/tree/2.3.4"
+                "source": "https://github.com/rectorphp/rector/tree/2.3.6"
             },
             "funding": [
                 {
@@ -432,7 +432,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2026-01-21T14:49:03+00:00"
+            "time": "2026-02-06T14:25:06+00:00"
         },
         {
             "name": "webmozart/assert",