diff --git a/src/CliProgram/Validation/Validators/DateTimeValidator.php b/src/CliProgram/Validation/Validators/DateTimeValidator.php
index 2dfa898..d1ffce9 100644
--- a/src/CliProgram/Validation/Validators/DateTimeValidator.php
+++ b/src/CliProgram/Validation/Validators/DateTimeValidator.php
@@ -29,7 +29,7 @@ class DateTimeValidator extends AbstractDateTimeValidator {
     /**
      * @inheritDoc
      */
-    public function getValidDefault (mixed $default): string|bool|int|float|array {
+    public function getValidDefault (mixed $default): string|bool|int|float|array|null {
         if ($default instanceof DateTimeInterface) {
             return $default->format('Y-m-d H:i:s');
         }
diff --git a/src/CliProgram/Validation/Validators/DateValidator.php b/src/CliProgram/Validation/Validators/DateValidator.php
index 5f99892..cc4595f 100644
--- a/src/CliProgram/Validation/Validators/DateValidator.php
+++ b/src/CliProgram/Validation/Validators/DateValidator.php
@@ -29,7 +29,7 @@ class DateValidator extends AbstractDateTimeValidator {
     /**
      * @inheritDoc
      */
-    public function getValidDefault (mixed $default): string|bool|int|float|array {
+    public function getValidDefault (mixed $default): string|bool|int|float|array|null {
         if ($default instanceof DateTimeInterface) {
             return $default->format('Y-m-d');
         }
diff --git a/src/CliProgram/Validation/Validators/EnumValidator.php b/src/CliProgram/Validation/Validators/EnumValidator.php
index 8974f35..83b39f1 100644
--- a/src/CliProgram/Validation/Validators/EnumValidator.php
+++ b/src/CliProgram/Validation/Validators/EnumValidator.php
@@ -43,7 +43,7 @@ class EnumValidator extends BasedValidator {
      *
      * @throws ReflectionException
      */
-    public function getValidDefault (mixed $default): string|bool|int|float|array {
+    public function getValidDefault (mixed $default): string|bool|int|float|array|null {
         if ($default instanceof UnitEnum) {
             $default = $default->name;
         }
diff --git a/src/CliProgram/Validation/Validators/IValidator.php b/src/CliProgram/Validation/Validators/IValidator.php
index 2190202..d83894b 100644
--- a/src/CliProgram/Validation/Validators/IValidator.php
+++ b/src/CliProgram/Validation/Validators/IValidator.php
@@ -13,9 +13,9 @@ interface IValidator {
      *
      * @param mixed $default The initial/given default value
      *
-     * @return string|bool|int|float|array The valid default value
+     * @return string|bool|int|float|array|null The valid default value
      */
-    public function getValidDefault (mixed $default): string|bool|int|float|array;
+    public function getValidDefault (mixed $default): string|bool|int|float|array|null;
 
     /**
      * Validate a value
diff --git a/src/CliProgram/Validation/Validators/TIdenticalValidDefaultValidator.php b/src/CliProgram/Validation/Validators/TIdenticalValidDefaultValidator.php
index 8a159e8..1a0fd2f 100644
--- a/src/CliProgram/Validation/Validators/TIdenticalValidDefaultValidator.php
+++ b/src/CliProgram/Validation/Validators/TIdenticalValidDefaultValidator.php
@@ -11,7 +11,7 @@ trait TIdenticalValidDefaultValidator {
     /**
      * @inheritDoc
      */
-    public function getValidDefault (mixed $default): string|bool|int|float|array {
+    public function getValidDefault (mixed $default): string|bool|int|float|array|null {
         return $default;
     }
 }
\ No newline at end of file
diff --git a/src/CliProgram/Validation/Validators/TimeValidator.php b/src/CliProgram/Validation/Validators/TimeValidator.php
index 43ed547..26ea54b 100644
--- a/src/CliProgram/Validation/Validators/TimeValidator.php
+++ b/src/CliProgram/Validation/Validators/TimeValidator.php
@@ -29,7 +29,7 @@ class TimeValidator extends AbstractDateTimeValidator {
     /**
      * @inheritDoc
      */
-    public function getValidDefault (mixed $default): string|bool|int|float|array {
+    public function getValidDefault (mixed $default): string|bool|int|float|array|null {
         if ($default instanceof DateTimeInterface) {
             return $default->format('H:i:s');
         }