diff --git a/src/Component/Serializer/ArraySupportDecorator.php b/src/Component/Serializer/ArraySupportDecorator.php
index 0e97d0e..e94de20 100644
--- a/src/Component/Serializer/ArraySupportDecorator.php
+++ b/src/Component/Serializer/ArraySupportDecorator.php
@@ -24,8 +24,7 @@ use Pnz\JsonException\Json;
  */
 class ArraySupportDecorator implements SerializerInterface
 {
-    /** @var \Liip\Serializer\SerializerInterface */
-    private $serializer;
+    private SerializerInterface $serializer;
 
     /**
      * ArraySupportDecorator constructor.
@@ -69,7 +68,7 @@ class ArraySupportDecorator implements SerializerInterface
     /**
      * @inheritDoc
      */
-    public function deserialize(string $data, string $type, string $format, ?Context $context = null)
+    public function deserialize(string $data, string $type, string $format, ?Context $context = null): mixed
     {
         if ('json' !== $format) {
             throw new UnsupportedFormatException('Liip serializer only supports JSON for now');
@@ -109,7 +108,7 @@ class ArraySupportDecorator implements SerializerInterface
      *
      * @return array<int|string, mixed>|object
      */
-    public function fromArray(array $data, string $type, ?Context $context = null)
+    public function fromArray(array $data, string $type, ?Context $context = null): mixed
     {
         if (static::isArrayType($type)) {
             return $this->decodeArray($data, $type, $context);
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 771a104..e2fe6ef 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -18,7 +18,10 @@ if (!is_file($autoloadFile = __DIR__ . '/../vendor/autoload.php')) {
 $loader = require $autoloadFile;
 $loader->add('RetailCrm\\TestUtils', __DIR__ . '/tests/utils');
 $loader->add('RetailCrm\\Tests', __DIR__ . '/src');
-AnnotationRegistry::registerLoader('class_exists');
+
+if (method_exists(AnnotationRegistry::class, 'registerLoader')) {
+    AnnotationRegistry::registerLoader('class_exists');
+}
 
 if (file_exists(__DIR__ . '/../.env')) {
     $dotenv = Dotenv\Dotenv::createImmutable(__DIR__ . '/..');
diff --git a/tests/src/ResourceGroup/CustomersTest.php b/tests/src/ResourceGroup/CustomersTest.php
index 3b99ed9..bf1691e 100644
--- a/tests/src/ResourceGroup/CustomersTest.php
+++ b/tests/src/ResourceGroup/CustomersTest.php
@@ -2698,14 +2698,15 @@ EOF;
         $response  = $client->customers->get(4770, $request);
 
         self::assertModelsCallback($json, $response, static function ($expected, $actual) {
-            $actualTags                                 = $actual['customer']['tags'];
-            $actual['customer']['tags']                 = array_filter(
-                array_map(static function ($tag) use ($actualTags) {
-                    if (in_array($tag['name'], $actualTags, true)) {
-                        return $tag;
-                    }
-                }, $expected['customer']['tags'])
-            );
+            // TODO: Check if it's really necessary to do tag conversion here. Maybe underlying serializer is broken.
+//            $actualTags                                 = $actual['customer']['tags'];
+//            $actual['customer']['tags']                 = array_filter(
+//                array_map(static function ($tag) use ($actualTags) {
+//                    if (in_array($tag['name'], $actualTags, true)) {
+//                        return $tag;
+//                    }
+//                }, $expected['customer']['tags'])
+//            );
 
             $expected['customer']['marginSumm']         = (float)$expected['customer']['marginSumm'];
             $expected['customer']['totalSumm']          = (float)$expected['customer']['totalSumm'];