diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa519ad9..717d1f9c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,7 @@
 # CHANGELOG
+## [3.0.8](https://github.com/apigee/apigee-client-php/milestone/32?closed=1)
+* [#379] Update option-resolver's symfony component version to its latest.
+
 ## [3.0.7](https://github.com/apigee/apigee-client-php/milestone/31?closed=1)
 * [#374] Bump minimum required version of symfony/serializer.
 * [#376] Remove symfony/serializer conflict and bump version.
diff --git a/src/Api/ApigeeX/Normalizer/AcceptedRatePlanNormalizer.php b/src/Api/ApigeeX/Normalizer/AcceptedRatePlanNormalizer.php
index e84a51c4..0b48ca33 100755
--- a/src/Api/ApigeeX/Normalizer/AcceptedRatePlanNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/AcceptedRatePlanNormalizer.php
@@ -21,6 +21,7 @@
 use Apigee\Edge\Api\ApigeeX\Entity\AcceptedRatePlanInterface;
 use Apigee\Edge\Api\Monetization\Normalizer\EntityNormalizer;
 use Apigee\Edge\Api\Monetization\Utility\TimezoneFixerHelperTrait;
+use ArrayObject;
 
 class AcceptedRatePlanNormalizer extends EntityNormalizer
 {
@@ -32,7 +33,7 @@ class AcceptedRatePlanNormalizer extends EntityNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var AcceptedRatePlanInterface $object */
         /** @var object $normalized */
diff --git a/src/Api/ApigeeX/Normalizer/ApiProductNormalizer.php b/src/Api/ApigeeX/Normalizer/ApiProductNormalizer.php
index 05ab9e6c..2f8d9ed2 100755
--- a/src/Api/ApigeeX/Normalizer/ApiProductNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/ApiProductNormalizer.php
@@ -21,6 +21,7 @@
 use Apigee\Edge\Api\ApigeeX\Entity\ApiProductInterface;
 use Apigee\Edge\Api\Monetization\NameConverter\ApiPackageNameConverter;
 use Apigee\Edge\Api\Monetization\Normalizer\EntityNormalizer;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -48,7 +49,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $normalized = parent::normalize($object, $format, $context);
 
diff --git a/src/Api/ApigeeX/Normalizer/AppGroupMembershipNormalizer.php b/src/Api/ApigeeX/Normalizer/AppGroupMembershipNormalizer.php
index f0fba9e9..49ecc403 100644
--- a/src/Api/ApigeeX/Normalizer/AppGroupMembershipNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/AppGroupMembershipNormalizer.php
@@ -19,6 +19,7 @@
 namespace Apigee\Edge\Api\ApigeeX\Normalizer;
 
 use Apigee\Edge\Api\ApigeeX\Structure\AppGroupMembership;
+use ArrayObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 class AppGroupMembershipNormalizer implements NormalizerInterface
@@ -29,7 +30,7 @@ class AppGroupMembershipNormalizer implements NormalizerInterface
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $normalized = [];
 
diff --git a/src/Api/ApigeeX/Normalizer/AppNormalizer.php b/src/Api/ApigeeX/Normalizer/AppNormalizer.php
index 3f7b3564..649c925b 100644
--- a/src/Api/ApigeeX/Normalizer/AppNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/AppNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Management\Entity\AppInterface;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 /**
@@ -41,7 +42,7 @@ public function supportsNormalization($data, $format = null)
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/ApigeeX/Normalizer/BillingTypeNormalizer.php b/src/Api/ApigeeX/Normalizer/BillingTypeNormalizer.php
index a7e73b0d..212eaca4 100644
--- a/src/Api/ApigeeX/Normalizer/BillingTypeNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/BillingTypeNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\ApigeeX\Entity\BillingTypeInterface;
 use Apigee\Edge\Api\Monetization\Normalizer\EntityNormalizer;
+use ArrayObject;
 
 class BillingTypeNormalizer extends EntityNormalizer
 {
@@ -29,7 +30,7 @@ class BillingTypeNormalizer extends EntityNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var BillingTypeInterface $object */
         /** @var object $normalized */
diff --git a/src/Api/ApigeeX/Normalizer/RatePlanNormalizer.php b/src/Api/ApigeeX/Normalizer/RatePlanNormalizer.php
index c8a45393..7aae5d2f 100755
--- a/src/Api/ApigeeX/Normalizer/RatePlanNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/RatePlanNormalizer.php
@@ -23,6 +23,7 @@
 use Apigee\Edge\Api\Monetization\Normalizer\EntityNormalizer;
 use Apigee\Edge\Api\Monetization\Utility\TimezoneFixerHelperTrait;
 use Apigee\Edge\Exception\UninitializedPropertyException;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -52,7 +53,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/ApigeeX/Normalizer/RatePlanNormalizerFactory.php b/src/Api/ApigeeX/Normalizer/RatePlanNormalizerFactory.php
index 3debb38a..82aa8a94 100755
--- a/src/Api/ApigeeX/Normalizer/RatePlanNormalizerFactory.php
+++ b/src/Api/ApigeeX/Normalizer/RatePlanNormalizerFactory.php
@@ -21,6 +21,7 @@
 use Apigee\Edge\Api\Monetization\Normalizer\CompanyRatePlanNormalizer;
 use Apigee\Edge\Api\Monetization\Normalizer\DeveloperCategoryRatePlanNormalizer;
 use Apigee\Edge\Api\Monetization\Normalizer\DeveloperRatePlanNormalizer;
+use ArrayObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 use Symfony\Component\Serializer\SerializerAwareInterface;
 use Symfony\Component\Serializer\SerializerAwareTrait;
@@ -56,7 +57,7 @@ public function __construct(array $normalizers = [])
      * @psalm-suppress InvalidNullableReturnType - There are going to be at
      * least one normalizer always that can normalize data here.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         foreach ($this->normalizers as $normalizer) {
             // Return the result from the first denormalizer that can
diff --git a/src/Api/ApigeeX/Normalizer/RatePlanRateNormalizer.php b/src/Api/ApigeeX/Normalizer/RatePlanRateNormalizer.php
index e2626f1c..8049388f 100755
--- a/src/Api/ApigeeX/Normalizer/RatePlanRateNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/RatePlanRateNormalizer.php
@@ -21,6 +21,7 @@
 use Apigee\Edge\Api\Monetization\Structure\RatePlanRate;
 use Apigee\Edge\Api\Monetization\Structure\RatePlanRateRevShare;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 
 class RatePlanRateNormalizer extends ObjectNormalizer
 {
@@ -30,7 +31,7 @@ class RatePlanRateNormalizer extends ObjectNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/ApigeeX/Normalizer/StandardRatePlanNormalizer.php b/src/Api/ApigeeX/Normalizer/StandardRatePlanNormalizer.php
index dda8754f..cf796a58 100755
--- a/src/Api/ApigeeX/Normalizer/StandardRatePlanNormalizer.php
+++ b/src/Api/ApigeeX/Normalizer/StandardRatePlanNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\ApigeeX\Entity\RatePlanInterface;
 use Apigee\Edge\Api\ApigeeX\Entity\StandardRatePlanInterface;
+use ArrayObject;
 
 class StandardRatePlanNormalizer extends RatePlanNormalizer
 {
@@ -29,7 +30,7 @@ class StandardRatePlanNormalizer extends RatePlanNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Management/Normalizer/AppCredentialNormalizer.php b/src/Api/Management/Normalizer/AppCredentialNormalizer.php
index 0903c413..8cc96833 100644
--- a/src/Api/Management/Normalizer/AppCredentialNormalizer.php
+++ b/src/Api/Management/Normalizer/AppCredentialNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Management\Entity\AppCredentialInterface;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 /**
@@ -41,7 +42,7 @@ public function supportsNormalization($data, $format = null)
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Management/Normalizer/AppNormalizer.php b/src/Api/Management/Normalizer/AppNormalizer.php
index 5010f277..635e7191 100644
--- a/src/Api/Management/Normalizer/AppNormalizer.php
+++ b/src/Api/Management/Normalizer/AppNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Management\Entity\AppInterface;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 /**
@@ -41,7 +42,7 @@ public function supportsNormalization($data, $format = null)
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Management/Normalizer/CompanyMembershipNormalizer.php b/src/Api/Management/Normalizer/CompanyMembershipNormalizer.php
index 68065c92..97f7f7cc 100644
--- a/src/Api/Management/Normalizer/CompanyMembershipNormalizer.php
+++ b/src/Api/Management/Normalizer/CompanyMembershipNormalizer.php
@@ -30,7 +30,7 @@ class CompanyMembershipNormalizer implements NormalizerInterface
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $normalized = [
             'developer' => [],
diff --git a/src/Api/Management/Query/StatsQueryNormalizer.php b/src/Api/Management/Query/StatsQueryNormalizer.php
index 532cbf57..083ac2df 100644
--- a/src/Api/Management/Query/StatsQueryNormalizer.php
+++ b/src/Api/Management/Query/StatsQueryNormalizer.php
@@ -19,6 +19,7 @@
 namespace Apigee\Edge\Api\Management\Query;
 
 use Apigee\Edge\Serializer\JsonEncoder;
+use ArrayObject;
 use DateTimeZone;
 use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
@@ -52,7 +53,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var StatsQueryInterface $object */
         // Transform the object to JSON and back to an array to keep boolean values as boolean.
diff --git a/src/Api/Monetization/Normalizer/AcceptedRatePlanNormalizer.php b/src/Api/Monetization/Normalizer/AcceptedRatePlanNormalizer.php
index 85242c3b..569967fe 100644
--- a/src/Api/Monetization/Normalizer/AcceptedRatePlanNormalizer.php
+++ b/src/Api/Monetization/Normalizer/AcceptedRatePlanNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Monetization\Entity\AcceptedRatePlanInterface;
 use Apigee\Edge\Api\Monetization\Utility\TimezoneFixerHelperTrait;
+use ArrayObject;
 
 class AcceptedRatePlanNormalizer extends EntityNormalizer
 {
@@ -31,7 +32,7 @@ class AcceptedRatePlanNormalizer extends EntityNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var AcceptedRatePlanInterface $object */
         /** @var object $normalized */
diff --git a/src/Api/Monetization/Normalizer/ApiPackageNormalizer.php b/src/Api/Monetization/Normalizer/ApiPackageNormalizer.php
index 1be6dfb4..53fe1454 100644
--- a/src/Api/Monetization/Normalizer/ApiPackageNormalizer.php
+++ b/src/Api/Monetization/Normalizer/ApiPackageNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Monetization\Entity\ApiPackageInterface;
 use Apigee\Edge\Api\Monetization\NameConverter\ApiPackageNameConverter;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -47,7 +48,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $normalized = (array) parent::normalize($object, $format, $context);
 
diff --git a/src/Api/Monetization/Normalizer/CompanyPaymentTransactionNormalizer.php b/src/Api/Monetization/Normalizer/CompanyPaymentTransactionNormalizer.php
index f86a78d6..335b2ee1 100644
--- a/src/Api/Monetization/Normalizer/CompanyPaymentTransactionNormalizer.php
+++ b/src/Api/Monetization/Normalizer/CompanyPaymentTransactionNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Monetization\NameConverter\CompanyRatePlanNameConverter;
 use Apigee\Edge\Api\Monetization\Structure\CompanyPaymentTransaction;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -47,7 +48,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/DateTimeZoneNormalizer.php b/src/Api/Monetization/Normalizer/DateTimeZoneNormalizer.php
index 8eba9f35..165cede8 100644
--- a/src/Api/Monetization/Normalizer/DateTimeZoneNormalizer.php
+++ b/src/Api/Monetization/Normalizer/DateTimeZoneNormalizer.php
@@ -18,6 +18,7 @@
 
 namespace Apigee\Edge\Api\Monetization\Normalizer;
 
+use ArrayObject;
 use DateTimeZone;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
@@ -26,7 +27,7 @@ class DateTimeZoneNormalizer implements NormalizerInterface
     /**
      * {@inheritdoc}
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         return $object->getName();
     }
diff --git a/src/Api/Monetization/Normalizer/DeveloperCategoryRatePlanNormalizer.php b/src/Api/Monetization/Normalizer/DeveloperCategoryRatePlanNormalizer.php
index c56ffd0d..417a08bf 100644
--- a/src/Api/Monetization/Normalizer/DeveloperCategoryRatePlanNormalizer.php
+++ b/src/Api/Monetization/Normalizer/DeveloperCategoryRatePlanNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Monetization\Entity\DeveloperCategoryRatePlanInterface;
 use Apigee\Edge\Api\Monetization\Entity\RatePlanInterface;
+use ArrayObject;
 
 class DeveloperCategoryRatePlanNormalizer extends RatePlanNormalizer
 {
@@ -29,7 +30,7 @@ class DeveloperCategoryRatePlanNormalizer extends RatePlanNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/DeveloperPaymentTransactionNormalizer.php b/src/Api/Monetization/Normalizer/DeveloperPaymentTransactionNormalizer.php
index 341a715a..a7e0bf94 100644
--- a/src/Api/Monetization/Normalizer/DeveloperPaymentTransactionNormalizer.php
+++ b/src/Api/Monetization/Normalizer/DeveloperPaymentTransactionNormalizer.php
@@ -19,6 +19,7 @@
 namespace Apigee\Edge\Api\Monetization\Normalizer;
 
 use Apigee\Edge\Api\Monetization\Structure\DeveloperPaymentTransaction;
+use ArrayObject;
 
 class DeveloperPaymentTransactionNormalizer extends PaymentTransactionNormalizer
 {
@@ -28,7 +29,7 @@ class DeveloperPaymentTransactionNormalizer extends PaymentTransactionNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/EntityNormalizer.php b/src/Api/Monetization/Normalizer/EntityNormalizer.php
index cbae260c..ff1584df 100644
--- a/src/Api/Monetization/Normalizer/EntityNormalizer.php
+++ b/src/Api/Monetization/Normalizer/EntityNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Monetization\Structure\NestedObjectReferenceInterface;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 use ReflectionObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
@@ -63,7 +64,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType stdClass is also an object.
      * @psalm-suppress InvalidPropertyFetch.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $normalized = (array) parent::normalize($object, $format, $context);
 
diff --git a/src/Api/Monetization/Normalizer/LegalEntityNormalizer.php b/src/Api/Monetization/Normalizer/LegalEntityNormalizer.php
index 3259c4e6..8c1519c1 100644
--- a/src/Api/Monetization/Normalizer/LegalEntityNormalizer.php
+++ b/src/Api/Monetization/Normalizer/LegalEntityNormalizer.php
@@ -22,6 +22,7 @@
 use Apigee\Edge\Api\Monetization\Entity\DeveloperInterface;
 use Apigee\Edge\Api\Monetization\Entity\LegalEntityInterface;
 use Apigee\Edge\Api\Monetization\NameConverter\LegalEntityNameConvert;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -49,7 +50,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/LegalEntityRatePlanNormalizer.php b/src/Api/Monetization/Normalizer/LegalEntityRatePlanNormalizer.php
index 50c51842..0fe3c49f 100644
--- a/src/Api/Monetization/Normalizer/LegalEntityRatePlanNormalizer.php
+++ b/src/Api/Monetization/Normalizer/LegalEntityRatePlanNormalizer.php
@@ -19,6 +19,7 @@
 namespace Apigee\Edge\Api\Monetization\Normalizer;
 
 use Apigee\Edge\Api\Monetization\Entity\RatePlanInterface;
+use ArrayObject;
 
 abstract class LegalEntityRatePlanNormalizer extends RatePlanNormalizer
 {
@@ -28,7 +29,7 @@ abstract class LegalEntityRatePlanNormalizer extends RatePlanNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/LegalEntityReportDefinitionNormalizer.php b/src/Api/Monetization/Normalizer/LegalEntityReportDefinitionNormalizer.php
index 54f1bb9e..2790aca3 100644
--- a/src/Api/Monetization/Normalizer/LegalEntityReportDefinitionNormalizer.php
+++ b/src/Api/Monetization/Normalizer/LegalEntityReportDefinitionNormalizer.php
@@ -18,6 +18,8 @@
 
 namespace Apigee\Edge\Api\Monetization\Normalizer;
 
+use ArrayObject;
+
 abstract class LegalEntityReportDefinitionNormalizer extends ReportDefinitionNormalizer
 {
     /**
@@ -26,7 +28,7 @@ abstract class LegalEntityReportDefinitionNormalizer extends ReportDefinitionNor
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/RatePlanNormalizer.php b/src/Api/Monetization/Normalizer/RatePlanNormalizer.php
index 95b008f4..240a7a56 100644
--- a/src/Api/Monetization/Normalizer/RatePlanNormalizer.php
+++ b/src/Api/Monetization/Normalizer/RatePlanNormalizer.php
@@ -22,6 +22,7 @@
 use Apigee\Edge\Api\Monetization\NameConverter\RatePlanNameConverter;
 use Apigee\Edge\Api\Monetization\Utility\TimezoneFixerHelperTrait;
 use Apigee\Edge\Exception\UninitializedPropertyException;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -51,7 +52,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/RatePlanNormalizerFactory.php b/src/Api/Monetization/Normalizer/RatePlanNormalizerFactory.php
index 0af7aff6..69dff853 100644
--- a/src/Api/Monetization/Normalizer/RatePlanNormalizerFactory.php
+++ b/src/Api/Monetization/Normalizer/RatePlanNormalizerFactory.php
@@ -18,6 +18,7 @@
 
 namespace Apigee\Edge\Api\Monetization\Normalizer;
 
+use ArrayObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 use Symfony\Component\Serializer\SerializerAwareInterface;
 use Symfony\Component\Serializer\SerializerAwareTrait;
@@ -53,7 +54,7 @@ public function __construct(array $normalizers = [])
      * @psalm-suppress InvalidNullableReturnType - There are going to be at
      * least one normalizer always that can normalize data here.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         foreach ($this->normalizers as $normalizer) {
             // Return the result from the first denormalizer that can
diff --git a/src/Api/Monetization/Normalizer/RatePlanRateNormalizer.php b/src/Api/Monetization/Normalizer/RatePlanRateNormalizer.php
index b8f47969..d4324550 100644
--- a/src/Api/Monetization/Normalizer/RatePlanRateNormalizer.php
+++ b/src/Api/Monetization/Normalizer/RatePlanRateNormalizer.php
@@ -21,6 +21,7 @@
 use Apigee\Edge\Api\Monetization\Structure\RatePlanRate;
 use Apigee\Edge\Api\Monetization\Structure\RatePlanRateRevShare;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 
 class RatePlanRateNormalizer extends ObjectNormalizer
 {
@@ -30,7 +31,7 @@ class RatePlanRateNormalizer extends ObjectNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/ReportCriteriaNormalizer.php b/src/Api/Monetization/Normalizer/ReportCriteriaNormalizer.php
index ff81fbd4..46a0c440 100644
--- a/src/Api/Monetization/Normalizer/ReportCriteriaNormalizer.php
+++ b/src/Api/Monetization/Normalizer/ReportCriteriaNormalizer.php
@@ -22,6 +22,7 @@
 use Apigee\Edge\Api\Monetization\Structure\Reports\Criteria\AbstractCriteria;
 use Apigee\Edge\Api\Monetization\Utility\TimezoneFixerHelperTrait;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 use DateTimeZone;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
@@ -59,7 +60,7 @@ public function __construct(string $organization, ?ClassMetadataFactoryInterface
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/ReportDefinitionNormalizer.php b/src/Api/Monetization/Normalizer/ReportDefinitionNormalizer.php
index 2cf26536..42be4c41 100644
--- a/src/Api/Monetization/Normalizer/ReportDefinitionNormalizer.php
+++ b/src/Api/Monetization/Normalizer/ReportDefinitionNormalizer.php
@@ -21,6 +21,7 @@
 use Apigee\Edge\Api\Monetization\Entity\ReportDefinitionInterface;
 use Apigee\Edge\Api\Monetization\NameConverter\ReportDefinitionNameConverter;
 use Apigee\Edge\Api\Monetization\Utility\ReportTypeFromCriteriaHelperTrait;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -50,7 +51,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var ReportDefinitionInterface $object */
         /** @var object $normalized */
diff --git a/src/Api/Monetization/Normalizer/StandardRatePlanNormalizer.php b/src/Api/Monetization/Normalizer/StandardRatePlanNormalizer.php
index 3914a8cf..643210a1 100644
--- a/src/Api/Monetization/Normalizer/StandardRatePlanNormalizer.php
+++ b/src/Api/Monetization/Normalizer/StandardRatePlanNormalizer.php
@@ -20,6 +20,7 @@
 
 use Apigee\Edge\Api\Monetization\Entity\RatePlanInterface;
 use Apigee\Edge\Api\Monetization\Entity\StandardRatePlanInterface;
+use ArrayObject;
 
 class StandardRatePlanNormalizer extends RatePlanNormalizer
 {
@@ -29,7 +30,7 @@ class StandardRatePlanNormalizer extends RatePlanNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/Api/Monetization/Normalizer/TermsAndConditionsNormalizer.php b/src/Api/Monetization/Normalizer/TermsAndConditionsNormalizer.php
index 80d5c8d1..a0791114 100644
--- a/src/Api/Monetization/Normalizer/TermsAndConditionsNormalizer.php
+++ b/src/Api/Monetization/Normalizer/TermsAndConditionsNormalizer.php
@@ -22,6 +22,7 @@
 use Apigee\Edge\Api\Monetization\NameConverter\TermsAndConditionsNameConverter;
 use Apigee\Edge\Api\Monetization\Utility\TimezoneFixerHelperTrait;
 use Apigee\Edge\Exception\UninitializedPropertyException;
+use ArrayObject;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
@@ -51,7 +52,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /** @var object $normalized */
         $normalized = parent::normalize($object, $format, $context);
diff --git a/src/ClientInterface.php b/src/ClientInterface.php
index 6ef44f15..b5078803 100644
--- a/src/ClientInterface.php
+++ b/src/ClientInterface.php
@@ -63,7 +63,7 @@ interface ClientInterface extends HttpClient
      */
     public const APIGEE_ON_GCP_ENDPOINT = 'https://apigee.googleapis.com/v1';
 
-    public const VERSION = '3.0.7';
+    public const VERSION = '3.0.8';
 
     /**
      * Allows access to the last request, response and exception.
diff --git a/src/Normalizer/CredentialProductNormalizer.php b/src/Normalizer/CredentialProductNormalizer.php
index 7a1b1adb..a7d293a1 100644
--- a/src/Normalizer/CredentialProductNormalizer.php
+++ b/src/Normalizer/CredentialProductNormalizer.php
@@ -33,7 +33,7 @@ class CredentialProductNormalizer implements NormalizerInterface
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /* @var \Apigee\Edge\Structure\CredentialProductInterface $object */
         $asObject = [
diff --git a/src/Normalizer/EdgeDateNormalizer.php b/src/Normalizer/EdgeDateNormalizer.php
index 77025207..45b1f028 100644
--- a/src/Normalizer/EdgeDateNormalizer.php
+++ b/src/Normalizer/EdgeDateNormalizer.php
@@ -18,6 +18,7 @@
 
 namespace Apigee\Edge\Normalizer;
 
+use ArrayObject;
 use DateTimeInterface;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
@@ -34,7 +35,7 @@ public function supportsNormalization($data, $format = null)
     /**
      * {@inheritdoc}
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         /* @var \DateTimeInterface $object */
         return $object->getTimestamp() * 1000;
diff --git a/src/Normalizer/KeyValueMapNormalizer.php b/src/Normalizer/KeyValueMapNormalizer.php
index 998c0427..4f2fa86c 100644
--- a/src/Normalizer/KeyValueMapNormalizer.php
+++ b/src/Normalizer/KeyValueMapNormalizer.php
@@ -19,6 +19,7 @@
 namespace Apigee\Edge\Normalizer;
 
 use Apigee\Edge\Structure\KeyValueMapInterface;
+use ArrayObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 /**
@@ -29,7 +30,7 @@ class KeyValueMapNormalizer implements NormalizerInterface
     /**
      * {@inheritdoc}
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $return = [];
         foreach ($object->values() as $key => $value) {
diff --git a/src/Normalizer/ObjectNormalizer.php b/src/Normalizer/ObjectNormalizer.php
index 644e9d21..103843ce 100644
--- a/src/Normalizer/ObjectNormalizer.php
+++ b/src/Normalizer/ObjectNormalizer.php
@@ -94,7 +94,7 @@ public function __construct(?ClassMetadataFactoryInterface $classMetadataFactory
      * @psalm-suppress PossiblyInvalidArgument First argument of array_filter is always an array.
      * @psalm-suppress PossiblyNullArgument First argument of array_filter is always an array.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $asArray = $this->objectNormalizer->normalize($object, $this->format, $context);
         // Exclude null values from the output, even if PATCH is not supported on Apigee Edge
diff --git a/src/Normalizer/PropertiesPropertyNormalizer.php b/src/Normalizer/PropertiesPropertyNormalizer.php
index 7818c637..11fd557c 100644
--- a/src/Normalizer/PropertiesPropertyNormalizer.php
+++ b/src/Normalizer/PropertiesPropertyNormalizer.php
@@ -34,7 +34,7 @@ class PropertiesPropertyNormalizer extends KeyValueMapNormalizer
      * @psalm-suppress InvalidReturnType Returning an object here is required
      * for creating a valid Apigee Edge request.
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         $return = [
             'property' => parent::normalize($object, $format, $context),
diff --git a/src/Serializer/EntitySerializer.php b/src/Serializer/EntitySerializer.php
index 24e90e31..d9334260 100755
--- a/src/Serializer/EntitySerializer.php
+++ b/src/Serializer/EntitySerializer.php
@@ -25,6 +25,7 @@
 use Apigee\Edge\Normalizer\EdgeDateNormalizer;
 use Apigee\Edge\Normalizer\KeyValueMapNormalizer;
 use Apigee\Edge\Normalizer\ObjectNormalizer;
+use ArrayObject;
 use Psr\Http\Message\ResponseInterface;
 use ReflectionMethod;
 use ReflectionObject;
@@ -90,7 +91,7 @@ public function supportsDenormalization($data, $type, $format = null)
     /**
      * {@inheritdoc}
      */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array|string|int|float|bool|ArrayObject|null
     {
         return $this->serializer->normalize($object, $format, $context);
     }