diff --git a/src/Storageless/Http/ClientFingerprint/Configuration.php b/src/Storageless/Http/ClientFingerprint/Configuration.php
index c243dabe..0f6f58a1 100644
--- a/src/Storageless/Http/ClientFingerprint/Configuration.php
+++ b/src/Storageless/Http/ClientFingerprint/Configuration.php
@@ -4,11 +4,10 @@
 
 namespace PSR7Sessions\Storageless\Http\ClientFingerprint;
 
-/** @immutable */
-final class Configuration
+final readonly class Configuration
 {
     /** @var list<Source> */
-    private readonly array $sources;
+    private array $sources;
 
     /**
      * @param list<Source> ...$sources
diff --git a/src/Storageless/Http/ClientFingerprint/RemoteAddr.php b/src/Storageless/Http/ClientFingerprint/RemoteAddr.php
index fec669dd..6a5ecba6 100644
--- a/src/Storageless/Http/ClientFingerprint/RemoteAddr.php
+++ b/src/Storageless/Http/ClientFingerprint/RemoteAddr.php
@@ -9,8 +9,7 @@
 use function array_key_exists;
 use function is_string;
 
-/** @immutable */
-final class RemoteAddr implements Source
+final readonly class RemoteAddr implements Source
 {
     private const SERVER_PARAM_NAME = 'REMOTE_ADDR';
 
diff --git a/src/Storageless/Http/ClientFingerprint/SameOriginRequest.php b/src/Storageless/Http/ClientFingerprint/SameOriginRequest.php
index b371d6ba..cdb039a2 100644
--- a/src/Storageless/Http/ClientFingerprint/SameOriginRequest.php
+++ b/src/Storageless/Http/ClientFingerprint/SameOriginRequest.php
@@ -19,22 +19,18 @@
 
 use const JSON_THROW_ON_ERROR;
 
-/**
- * @internal
- *
- * @immutable
- */
-final class SameOriginRequest implements Constraint
+/** @internal */
+final readonly class SameOriginRequest implements Constraint
 {
     public const CLAIM = 'fp';
 
     /** @var list<Source> */
-    private readonly array $sources;
+    private array $sources;
     /** @var non-empty-string */
-    private readonly string $currentRequestFingerprint;
+    private string $currentRequestFingerprint;
 
     public function __construct(
-        private readonly Configuration $configuration,
+        private Configuration $configuration,
         ServerRequestInterface $serverRequest,
     ) {
         $this->sources = $this->configuration->sources();
diff --git a/src/Storageless/Http/ClientFingerprint/UserAgent.php b/src/Storageless/Http/ClientFingerprint/UserAgent.php
index 5463b62e..ea379d01 100644
--- a/src/Storageless/Http/ClientFingerprint/UserAgent.php
+++ b/src/Storageless/Http/ClientFingerprint/UserAgent.php
@@ -6,8 +6,7 @@
 
 use Psr\Http\Message\ServerRequestInterface;
 
-/** @immutable */
-final class UserAgent implements Source
+final readonly class UserAgent implements Source
 {
     public function extractFrom(ServerRequestInterface $request): string
     {
diff --git a/src/Storageless/Http/SessionMiddleware.php b/src/Storageless/Http/SessionMiddleware.php
index e7240984..2c3f6870 100644
--- a/src/Storageless/Http/SessionMiddleware.php
+++ b/src/Storageless/Http/SessionMiddleware.php
@@ -43,14 +43,13 @@
 
 use function sprintf;
 
-/** @immutable */
-final class SessionMiddleware implements MiddlewareInterface
+final readonly class SessionMiddleware implements MiddlewareInterface
 {
     public const SESSION_CLAIM     = 'session-data';
     public const SESSION_ATTRIBUTE = 'session';
 
     public function __construct(
-        private readonly Configuration $config,
+        private Configuration $config,
     ) {
     }