diff --git a/ChangeLog-11.5.md b/ChangeLog-11.5.md
index 25a5d82f633..7b48ff1bef9 100644
--- a/ChangeLog-11.5.md
+++ b/ChangeLog-11.5.md
@@ -2,6 +2,12 @@
 
 All notable changes of the PHPUnit 11.5 release series are documented in this file using the [Keep a CHANGELOG](https://keepachangelog.com/) principles.
 
+## [11.5.2] - 2024-MM-DD
+
+### Fixed
+
+* [#6082](https://github.com/sebastianbergmann/phpunit/issues/6082): `assertArrayHasKey()`, `assertArrayNotHasKey()`, `arrayHasKey()`, and `ArrayHasKey::__construct()` do not support all possible key types
+
 ## [11.5.1] - 2024-12-11
 
 ### Added
@@ -37,5 +43,6 @@ All notable changes of the PHPUnit 11.5 release series are documented in this fi
 * [#6055](https://github.com/sebastianbergmann/phpunit/issues/6055): `assertNotContainsOnly()` (use `assertContainsNotOnlyArray()`, `assertContainsNotOnlyBool()`, `assertContainsNotOnlyCallable()`, `assertContainsNotOnlyFloat()`, `assertContainsNotOnlyInt()`, `assertContainsNotOnlyIterable()`, `assertContainsNotOnlyNumeric()`, `assertContainsNotOnlyObject()`, `assertContainsNotOnlyResource()`, `assertContainsNotOnlyClosedResource()`, `assertContainsNotOnlyScalar()`, or `assertContainsNotOnlyString()` instead)
 * [#6059](https://github.com/sebastianbergmann/phpunit/issues/6059): `containsOnly()` (use `containsOnlyArray()`, `containsOnlyBool()`, `containsOnlyCallable()`, `containsOnlyFloat()`, `containsOnlyInt()`, `containsOnlyIterable()`, `containsOnlyNumeric()`, `containsOnlyObject()`, `containsOnlyResource()`, `containsOnlyClosedResource()`, `containsOnlyScalar()`, or `containsOnlyString()` instead)
 
+[11.5.2]: https://github.com/sebastianbergmann/phpunit/compare/11.5.1...11.5
 [11.5.1]: https://github.com/sebastianbergmann/phpunit/compare/11.5.0...11.5.1
 [11.5.0]: https://github.com/sebastianbergmann/phpunit/compare/11.4.4...11.5.0
diff --git a/src/Framework/Assert.php b/src/Framework/Assert.php
index 056a1bd0ee8..37ee4a8f719 100644
--- a/src/Framework/Assert.php
+++ b/src/Framework/Assert.php
@@ -170,7 +170,7 @@ final public static function assertArrayIsIdenticalToArrayIgnoringListOfKeys(arr
      * @throws Exception
      * @throws ExpectationFailedException
      */
-    final public static function assertArrayHasKey(int|string $key, array|ArrayAccess $array, string $message = ''): void
+    final public static function assertArrayHasKey(mixed $key, array|ArrayAccess $array, string $message = ''): void
     {
         $constraint = new ArrayHasKey($key);
 
@@ -185,7 +185,7 @@ final public static function assertArrayHasKey(int|string $key, array|ArrayAcces
      * @throws Exception
      * @throws ExpectationFailedException
      */
-    final public static function assertArrayNotHasKey(int|string $key, array|ArrayAccess $array, string $message = ''): void
+    final public static function assertArrayNotHasKey(mixed $key, array|ArrayAccess $array, string $message = ''): void
     {
         $constraint = new LogicalNot(
             new ArrayHasKey($key),
@@ -2865,7 +2865,7 @@ final public static function containsOnlyInstancesOf(string $className): Travers
         return new TraversableContainsOnly($className, false);
     }
 
-    final public static function arrayHasKey(int|string $key): ArrayHasKey
+    final public static function arrayHasKey(mixed $key): ArrayHasKey
     {
         return new ArrayHasKey($key);
     }
diff --git a/src/Framework/Assert/Functions.php b/src/Framework/Assert/Functions.php
index 0f66023c59c..cfe2557e300 100644
--- a/src/Framework/Assert/Functions.php
+++ b/src/Framework/Assert/Functions.php
@@ -166,7 +166,7 @@ function assertArrayIsIdenticalToArrayIgnoringListOfKeys(array $expected, array
      *
      * @see Assert::assertArrayHasKey
      */
-    function assertArrayHasKey(int|string $key, array|ArrayAccess $array, string $message = ''): void
+    function assertArrayHasKey(mixed $key, array|ArrayAccess $array, string $message = ''): void
     {
         Assert::assertArrayHasKey(...func_get_args());
     }
@@ -185,7 +185,7 @@ function assertArrayHasKey(int|string $key, array|ArrayAccess $array, string $me
      *
      * @see Assert::assertArrayNotHasKey
      */
-    function assertArrayNotHasKey(int|string $key, array|ArrayAccess $array, string $message = ''): void
+    function assertArrayNotHasKey(mixed $key, array|ArrayAccess $array, string $message = ''): void
     {
         Assert::assertArrayNotHasKey(...func_get_args());
     }
@@ -3093,7 +3093,7 @@ function containsOnlyInstancesOf(string $className): TraversableContainsOnly
 }
 
 if (!function_exists('PHPUnit\Framework\arrayHasKey')) {
-    function arrayHasKey(int|string $key): ArrayHasKey
+    function arrayHasKey(mixed $key): ArrayHasKey
     {
         return Assert::arrayHasKey(...func_get_args());
     }
diff --git a/src/Framework/Constraint/Traversable/ArrayHasKey.php b/src/Framework/Constraint/Traversable/ArrayHasKey.php
index cc2482b313a..fa8d2744111 100644
--- a/src/Framework/Constraint/Traversable/ArrayHasKey.php
+++ b/src/Framework/Constraint/Traversable/ArrayHasKey.php
@@ -19,9 +19,9 @@
  */
 final class ArrayHasKey extends Constraint
 {
-    private readonly int|string $key;
+    private readonly mixed $key;
 
-    public function __construct(int|string $key)
+    public function __construct(mixed $key)
     {
         $this->key = $key;
     }