diff --git a/lib/Controller/PublicSessionController.php b/lib/Controller/PublicSessionController.php
index 4f01142784d..3d0da080e8c 100644
--- a/lib/Controller/PublicSessionController.php
+++ b/lib/Controller/PublicSessionController.php
@@ -80,7 +80,7 @@ protected function isPasswordProtected(): bool {
 
 	#[NoAdminRequired]
 	#[PublicPage]
-	public function create(string $token, string $file = null, ?string $guestName = null): DataResponse {
+	public function create(string $token, ?string $file = null, ?string $guestName = null): DataResponse {
 		return $this->apiService->create(null, $file, $token, $guestName);
 	}
 
@@ -107,7 +107,7 @@ public function sync(string $token, int $version = 0): DataResponse {
 	#[NoAdminRequired]
 	#[PublicPage]
 	#[RequireDocumentSession]
-	public function save(string $token, int $version = 0, string $autosaveContent = null, string $documentState = null, bool $force = false, bool $manualSave = false): DataResponse {
+	public function save(string $token, int $version = 0, ?string $autosaveContent = null, ?string $documentState = null, bool $force = false, bool $manualSave = false): DataResponse {
 		return $this->apiService->save($this->getSession(), $this->getDocument(), $version, $autosaveContent, $documentState, $force, $manualSave, $token);
 	}
 
diff --git a/lib/Controller/SessionController.php b/lib/Controller/SessionController.php
index 9de585d394b..aa935f57879 100644
--- a/lib/Controller/SessionController.php
+++ b/lib/Controller/SessionController.php
@@ -57,7 +57,7 @@ public function __construct(
 	}
 
 	#[NoAdminRequired]
-	public function create(int $fileId = null, string $file = null): DataResponse {
+	public function create(?int $fileId = null, ?string $file = null): DataResponse {
 		return $this->apiService->create($fileId, $file, null, null);
 	}
 
@@ -94,7 +94,7 @@ public function sync(int $version = 0): DataResponse {
 	#[NoAdminRequired]
 	#[PublicPage]
 	#[RequireDocumentSession]
-	public function save(int $version = 0, string $autosaveContent = null, string $documentState = null, bool $force = false, bool $manualSave = false): DataResponse {
+	public function save(int $version = 0, ?string $autosaveContent = null, ?string $documentState = null, bool $force = false, bool $manualSave = false): DataResponse {
 		try {
 			$this->loginSessionUser();
 			return $this->apiService->save($this->getSession(), $this->getDocument(), $version, $autosaveContent, $documentState, $force, $manualSave);
diff --git a/lib/Service/DocumentService.php b/lib/Service/DocumentService.php
index fa3c34e5b8d..d6c8edbe98b 100644
--- a/lib/Service/DocumentService.php
+++ b/lib/Service/DocumentService.php
@@ -26,7 +26,7 @@
 
 namespace OCA\Text\Service;
 
-use \InvalidArgumentException;
+use InvalidArgumentException;
 use OCA\Text\AppInfo\Application;
 use OCA\Text\Db\Document;
 use OCA\Text\Db\DocumentMapper;
diff --git a/lib/Service/SessionService.php b/lib/Service/SessionService.php
index e24204e201d..744b763cbf6 100644
--- a/lib/Service/SessionService.php
+++ b/lib/Service/SessionService.php
@@ -85,7 +85,7 @@ public function __construct(
 		$this->cache = $cacheFactory->createDistributed('text_sessions');
 	}
 
-	public function initSession(int $documentId, string $guestName = null): Session {
+	public function initSession(int $documentId, ?string $guestName = null): Session {
 		$session = new Session();
 		$session->setDocumentId($documentId);
 		$userName = $this->userId ? $this->userId : $guestName;
@@ -236,7 +236,7 @@ public function updateSessionAwareness(Session $session, string $message): Sessi
 		return $this->sessionMapper->update($session);
 	}
 
-	private function getColorForGuestName(string $guestName = null): string {
+	private function getColorForGuestName(?string $guestName = null): string {
 		$guestName = $this->userId ?? $guestName;
 		$uniqueGuestId = !empty($guestName) ? $guestName : $this->secureRandom->generate(12);
 		$color = $this->avatarManager->getGuestAvatar($uniqueGuestId)->avatarBackgroundColor($uniqueGuestId);
diff --git a/tests/unit/Controller/UserApiControllerTest.php b/tests/unit/Controller/UserApiControllerTest.php
index 14db310e38e..9d4c3bfc8ba 100644
--- a/tests/unit/Controller/UserApiControllerTest.php
+++ b/tests/unit/Controller/UserApiControllerTest.php
@@ -2,11 +2,11 @@
 
 namespace OCA\Text\Controller;
 
-use \OCP\IRequest;
 use OCA\Text\Db\Session;
 use OCA\Text\Service\SessionService;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\Collaboration\Collaborators\ISearch;
+use OCP\IRequest;
 use OCP\IUserManager;
 use OCP\IUserSession;
 use Test\TestCase;