diff --git a/wcfsetup/install/files/lib/system/form/builder/field/SelectFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/SelectFormField.class.php
index abc8177f86a..f42c3a9a66c 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/SelectFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/SelectFormField.class.php
@@ -39,7 +39,7 @@ final class SelectFormField extends AbstractFormField implements
     /**
      * @since 6.2
      */
-    private ?string $defaultValue = null;
+    private string|int|null $defaultValue = null;
 
     /**
      * @inheritDoc
@@ -117,7 +117,7 @@ public function ignoreInvalidValues(bool $ignoreInvalidValues = true): self
      *
      * @since 6.2
      */
-    public function defaultValue(?string $defaultValue = null): self
+    public function defaultValue(string|int|null $defaultValue = null): self
     {
         if ($defaultValue !== null && !isset($this->getOptions()[$defaultValue])) {
             throw new \InvalidArgumentException("Unknown default value '{$defaultValue}' for field '{$this->getId()}'.");