diff --git a/src/lib/Siteaccess/NonAdminSiteaccessResolver.php b/src/lib/Siteaccess/NonAdminSiteaccessResolver.php
index b04c8f67af..e2d9090368 100644
--- a/src/lib/Siteaccess/NonAdminSiteaccessResolver.php
+++ b/src/lib/Siteaccess/NonAdminSiteaccessResolver.php
@@ -49,8 +49,8 @@ public function getSiteaccessesForLocation(
      */
     public function getSiteAccessesListForLocation(
         Location $location,
-        int $versionNo = null,
-        string $languageCode = null
+        ?int $versionNo = null,
+        ?string $languageCode = null
     ): array {
         return array_filter(
             $this->siteaccessResolver->getSiteAccessesListForLocation($location, $versionNo, $languageCode),
diff --git a/src/lib/Siteaccess/SiteaccessResolver.php b/src/lib/Siteaccess/SiteaccessResolver.php
index d746ed78c4..bc395353fb 100644
--- a/src/lib/Siteaccess/SiteaccessResolver.php
+++ b/src/lib/Siteaccess/SiteaccessResolver.php
@@ -63,8 +63,8 @@ public function getSiteaccessesForLocation(
      */
     public function getSiteAccessesListForLocation(
         Location $location,
-        int $versionNo = null,
-        string $languageCode = null
+        ?int $versionNo = null,
+        ?string $languageCode = null
     ): array {
         $contentInfo = $location->getContentInfo();
         $versionInfo = $this->contentService->loadVersionInfo($contentInfo, $versionNo);
diff --git a/src/lib/Siteaccess/SiteaccessResolverInterface.php b/src/lib/Siteaccess/SiteaccessResolverInterface.php
index 75332e1074..1c9639ec15 100644
--- a/src/lib/Siteaccess/SiteaccessResolverInterface.php
+++ b/src/lib/Siteaccess/SiteaccessResolverInterface.php
@@ -34,8 +34,8 @@ public function getSiteaccessesForLocation(
      */
     public function getSiteAccessesListForLocation(
         Location $location,
-        int $versionNo = null,
-        string $languageCode = null
+        ?int $versionNo = null,
+        ?string $languageCode = null
     ): array;
 
     /**