diff --git a/composer.json b/composer.json
index 4c79d16..c5c5157 100644
--- a/composer.json
+++ b/composer.json
@@ -32,7 +32,7 @@
         "php-parallel-lint/php-console-highlighter": "^1.0",
         "php-parallel-lint/php-parallel-lint": "^1.3",
         "phpstan/extension-installer": "^1.1",
-        "phpstan/phpstan": "~1.10.0",
+        "phpstan/phpstan": "^1.11.0",
         "phpstan/phpstan-mockery": "^1.0",
         "phpstan/phpstan-phpunit": "^1.1",
         "psalm/plugin-mockery": "^1.0.0",
@@ -64,6 +64,7 @@
             "phpstan/extension-installer": true,
             "ramsey/composer-repl": true
         },
+        "lock": false,
         "sort-packages": true
     },
     "extra": {
diff --git a/src/OpenFeatureAPI.php b/src/OpenFeatureAPI.php
index 3e761f5..66eeb78 100644
--- a/src/OpenFeatureAPI.php
+++ b/src/OpenFeatureAPI.php
@@ -42,7 +42,7 @@ final class OpenFeatureAPI implements API, LoggerAwareInterface
 
     /** @var (Client & ProviderAware) | null $defaultClient */
     private $defaultClient;
-    /** @var Array<string,Client & ProviderAware> $clientMap */
+    /** @var array<string,Client & ProviderAware> $clientMap */
     private array $clientMap = [];
 
     /** @var Hook[] $hooks */
diff --git a/src/OpenFeatureClient.php b/src/OpenFeatureClient.php
index 28aae6c..f90f0c2 100644
--- a/src/OpenFeatureClient.php
+++ b/src/OpenFeatureClient.php
@@ -5,7 +5,6 @@
 namespace OpenFeature;
 
 use OpenFeature\implementation\common\Metadata;
-use OpenFeature\implementation\common\ValueTypeValidator;
 use OpenFeature\implementation\errors\InvalidResolutionValueError;
 use OpenFeature\implementation\flags\EvaluationContext;
 use OpenFeature\implementation\flags\EvaluationDetailsBuilder;
@@ -346,7 +345,7 @@ private function evaluateFlag(
                 $mergedContext,
             );
 
-            if (!$resolutionDetails->getError() && !ValueTypeValidator::is($flagValueType, $resolutionDetails->getValue())) {
+            if (!$resolutionDetails->getError() && $flagValueType !== FlagValueType::tryFromResolutionDetails($resolutionDetails)) {
                 throw new InvalidResolutionValueError($flagValueType->value);
             }
 
@@ -388,33 +387,14 @@ private function createProviderEvaluation(
         Provider $provider,
         EvaluationContextInterface $context,
     ): ResolutionDetails {
-        switch ($type->value) {
-            case FlagValueType::Boolean->value:
-                /** @var bool $defaultValue */;
-                $defaultValue = $defaultValue;
-
-                return $provider->resolveBooleanValue($key, $defaultValue, $context);
-            case FlagValueType::String->value:
-                /** @var string $defaultValue */;
-                $defaultValue = $defaultValue;
-
-                return $provider->resolveStringValue($key, $defaultValue, $context);
-            case FlagValueType::Integer->value:
-                /** @var int $defaultValue */;
-                $defaultValue = $defaultValue;
-
-                return $provider->resolveIntegerValue($key, $defaultValue, $context);
-            case FlagValueType::Float->value:
-                /** @var float $defaultValue */;
-                $defaultValue = $defaultValue;
-
-                return $provider->resolveFloatValue($key, $defaultValue, $context);
-            case FlagValueType::Object->value:
-                /** @var mixed[] $defaultValue */;
-                $defaultValue = $defaultValue;
-
-                return $provider->resolveObjectValue($key, $defaultValue, $context);
-        }
+        /** @psalm-suppress InvalidArgument,PossiblyInvalidArgument,PossiblyInvalidCast */
+        return match ($type) {
+            FlagValueType::Boolean => $provider->resolveBooleanValue($key, $defaultValue, $context), // @phpstan-ignore argument.type
+            FlagValueType::String => $provider->resolveStringValue($key, $defaultValue, $context), // @phpstan-ignore argument.type
+            FlagValueType::Integer => $provider->resolveIntegerValue($key, $defaultValue, $context), // @phpstan-ignore argument.type
+            FlagValueType::Float => $provider->resolveFloatValue($key, $defaultValue, $context), // @phpstan-ignore argument.type
+            FlagValueType::Object => $provider->resolveObjectValue($key, $defaultValue, $context), // @phpstan-ignore argument.type
+        };
     }
 
     private function determineProvider(): Provider
diff --git a/src/implementation/common/ArrayHelper.php b/src/implementation/common/ArrayHelper.php
index 4521cfa..6145348 100644
--- a/src/implementation/common/ArrayHelper.php
+++ b/src/implementation/common/ArrayHelper.php
@@ -4,9 +4,8 @@
 
 namespace OpenFeature\implementation\common;
 
+use function array_is_list;
 use function array_keys;
-use function is_int;
-use function sizeof;
 
 class ArrayHelper
 {
@@ -19,17 +18,8 @@ class ArrayHelper
      *
      * @return array<int, string>
      */
-    public static function getStringKeys(array $array)
+    public static function getStringKeys(array $array): array
     {
-        $keys = array_keys($array);
-
-        if (sizeof($keys) === 0 || is_int($keys[0])) {
-            return [];
-        }
-
-        /** @var array<int, string> $stringKeys */
-        $stringKeys = $keys;
-
-        return $stringKeys;
+        return array_is_list($array) ? [] : array_keys($array);
     }
 }
diff --git a/src/implementation/common/StringHelper.php b/src/implementation/common/StringHelper.php
index 447a72d..628e4cf 100644
--- a/src/implementation/common/StringHelper.php
+++ b/src/implementation/common/StringHelper.php
@@ -4,28 +4,18 @@
 
 namespace OpenFeature\implementation\common;
 
-use function strlen;
-use function strtolower;
-use function strtoupper;
-use function substr;
+use function lcfirst;
+use function ucfirst;
 
 class StringHelper
 {
     public static function capitalize(string $input): string
     {
-        return match (strlen($input)) {
-            0 => '',
-            1 => strtoupper($input),
-            default => strtoupper(substr($input, 0, 1)) . substr($input, 1),
-        };
+        return ucfirst($input);
     }
 
     public static function decapitalize(string $input): string
     {
-        return match (strlen($input)) {
-            0 => '',
-            1 => strtolower($input),
-            default => strtolower(substr($input, 0, 1)) . substr($input, 1),
-        };
+        return lcfirst($input);
     }
 }
diff --git a/src/implementation/common/ValueTypeValidator.php b/src/implementation/common/ValueTypeValidator.php
deleted file mode 100644
index 3fd12e7..0000000
--- a/src/implementation/common/ValueTypeValidator.php
+++ /dev/null
@@ -1,87 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace OpenFeature\implementation\common;
-
-use DateTime;
-use OpenFeature\interfaces\flags\FlagValueType;
-
-use function is_array;
-use function is_bool;
-use function is_float;
-use function is_int;
-use function is_string;
-
-class ValueTypeValidator
-{
-    /**
-     * Validates whether the value is a boolean type
-     */
-    public static function isBoolean(mixed $value): bool
-    {
-        return is_bool($value);
-    }
-
-    /**
-     * Validates whether the value is a string type
-     */
-    public static function isString(mixed $value): bool
-    {
-        return is_string($value);
-    }
-
-    /**
-     * Validates whether the value is an integer type
-     */
-    public static function isInteger(mixed $value): bool
-    {
-        return is_int($value);
-    }
-
-    /**
-     * Validates whether the value is a float type
-     */
-    public static function isFloat(mixed $value): bool
-    {
-        return is_float($value);
-    }
-
-    /**
-     * Validates whether the value is a structure
-     */
-    public static function isStructure(mixed $value): bool
-    {
-        return self::isArray($value);
-    }
-
-    /**
-     * Validates whether the value is an Array type
-     */
-    public static function isArray(mixed $value): bool
-    {
-        return is_array($value);
-    }
-
-    /**
-     * Validates whether the value is a DateTime type
-     */
-    public static function isDateTime(mixed $value): bool
-    {
-        return $value instanceof DateTime;
-    }
-
-    /**
-     * Validates whether the value is valid for the given type
-     */
-    public static function is(FlagValueType $type, mixed $value): bool
-    {
-        return match ($type) {
-            FlagValueType::Boolean => self::isBoolean($value),
-            FlagValueType::Float => self::isFloat($value),
-            FlagValueType::Integer => self::isInteger($value),
-            FlagValueType::String => self::isString($value),
-            FlagValueType::Object => self::isStructure($value) || self::isArray($value),
-        };
-    }
-}
diff --git a/src/implementation/events/EventMetadata.php b/src/implementation/events/EventMetadata.php
index 80bde7a..a8ae266 100644
--- a/src/implementation/events/EventMetadata.php
+++ b/src/implementation/events/EventMetadata.php
@@ -13,7 +13,7 @@
 class EventMetadata implements EventMetadataInterface
 {
     /**
-     * @param Array<string, bool|string|int|float> $eventMetadataMap
+     * @param array<string, bool|string|int|float> $eventMetadataMap
      */
     public function __construct(protected array $eventMetadataMap = [])
     {
@@ -27,7 +27,7 @@ public function has(string $key): bool
     /**
      * Return key-type pairs of the EventMetadata
      *
-     * @return Array<int, string>
+     * @return array<int, string>
      */
     public function keys(): array
     {
@@ -44,7 +44,7 @@ public function get(string $key): bool | string | int | float | null
     }
 
     /**
-     * @return Array<string, bool|string|int|float>
+     * @return array<string, bool|string|int|float>
      */
     public function toArray(): array
     {
diff --git a/src/implementation/events/HandlerAdderTrait.php b/src/implementation/events/HandlerAdderTrait.php
index 0882983..5916c01 100644
--- a/src/implementation/events/HandlerAdderTrait.php
+++ b/src/implementation/events/HandlerAdderTrait.php
@@ -7,7 +7,7 @@
 trait HandlerAdderTrait
 {
     /**
-     * @var Array<callable> $handlers
+     * @var array<callable> $handlers
      */
     private array $handlers = [];
 }
diff --git a/src/implementation/flags/Attributes.php b/src/implementation/flags/Attributes.php
index 34837f3..25120a5 100644
--- a/src/implementation/flags/Attributes.php
+++ b/src/implementation/flags/Attributes.php
@@ -11,7 +11,7 @@
 class Attributes implements AttributesInterface
 {
     /**
-     * @param Array<array-key, bool|string|int|float|DateTime|mixed[]|null> $attributesMap
+     * @param array<array-key, bool|string|int|float|DateTime|mixed[]|null> $attributesMap
      */
     public function __construct(protected array $attributesMap = [])
     {
@@ -20,7 +20,7 @@ public function __construct(protected array $attributesMap = [])
     /**
      * Return key-type pairs of the attributes
      *
-     * @return Array<int, string>
+     * @return array<int, string>
      */
     public function keys(): array
     {
@@ -36,7 +36,7 @@ public function get(string $key): bool | string | int | float | DateTime | array
     }
 
     /**
-     * @return Array<array-key, bool|string|int|float|DateTime|mixed[]|null>
+     * @return array<array-key, bool|string|int|float|DateTime|mixed[]|null>
      */
     public function toArray(): array
     {
diff --git a/src/implementation/flags/FlagMetadata.php b/src/implementation/flags/FlagMetadata.php
index 01a26f3..ce287a7 100644
--- a/src/implementation/flags/FlagMetadata.php
+++ b/src/implementation/flags/FlagMetadata.php
@@ -10,7 +10,7 @@
 class FlagMetadata implements FlagMetadataInterface
 {
     /**
-     * @param Array<array-key, bool|string|int|float> $metadata
+     * @param array<array-key, bool|string|int|float> $metadata
      */
     public function __construct(protected array $metadata = [])
     {
@@ -19,7 +19,7 @@ public function __construct(protected array $metadata = [])
     /**
      * Return key-type pairs of the attributes
      *
-     * @return Array<int, string>
+     * @return array<int, string>
      */
     public function keys(): array
     {
@@ -32,7 +32,7 @@ public function get(string $key): bool | string | int | float | null
     }
 
     /**
-     * @return Array<array-key, bool|string|int|float>
+     * @return array<array-key, bool|string|int|float>
      */
     public function toArray(): array
     {
diff --git a/src/implementation/flags/MutableAttributes.php b/src/implementation/flags/MutableAttributes.php
index 662ce7c..73b152b 100644
--- a/src/implementation/flags/MutableAttributes.php
+++ b/src/implementation/flags/MutableAttributes.php
@@ -17,11 +17,11 @@ public static function from(AttributesInterface $attributes): MutableAttributes
         $attributeMap = array_reduce(
             $attributes->keys(),
             /**
-             * @param Array<string, bool|string|int|float|DateTime|mixed[]|null> $map
+             * @param array<string, bool|string|int|float|DateTime|mixed[]|null> $map
              *
-             * @return Array<string, bool|string|int|float|DateTime|mixed[]|null>
+             * @return array<string, bool|string|int|float|DateTime|mixed[]|null>
              */
-            function (array $map, string $key) use ($attributes) {
+            static function (array $map, string $key) use ($attributes) {
                 $map[$key] = $attributes->get($key);
 
                 return $map;
diff --git a/src/implementation/hooks/HookHints.php b/src/implementation/hooks/HookHints.php
index a237777..958656d 100644
--- a/src/implementation/hooks/HookHints.php
+++ b/src/implementation/hooks/HookHints.php
@@ -13,7 +13,7 @@
 class HookHints implements HookHintsInterface
 {
     /**
-     * @param Array<string, bool | string | float | int | DateTime | mixed[] | null> $hints
+     * @param array<string, bool | string | float | int | DateTime | mixed[] | null> $hints
      */
     public function __construct(private readonly array $hints = [])
     {
diff --git a/src/interfaces/events/EventDetails.php b/src/interfaces/events/EventDetails.php
index 8922636..e1dfb68 100644
--- a/src/interfaces/events/EventDetails.php
+++ b/src/interfaces/events/EventDetails.php
@@ -9,7 +9,7 @@ interface EventDetails
     public function getClientName(): string;
 
   /**
-   * @return Array<string>
+   * @return array<string>
    */
     public function getChangedFlags(): array;
 
diff --git a/src/interfaces/events/EventMetadata.php b/src/interfaces/events/EventMetadata.php
index 25cff73..908143a 100644
--- a/src/interfaces/events/EventMetadata.php
+++ b/src/interfaces/events/EventMetadata.php
@@ -16,7 +16,7 @@ public function get(string $key): bool | string | int | float | null;
     public function keys(): array;
 
     /**
-     * @return Array<array-key, bool|string|int|float>
+     * @return array<array-key, bool|string|int|float>
      */
     public function toArray(): array;
 }
diff --git a/src/interfaces/flags/Attributes.php b/src/interfaces/flags/Attributes.php
index 1adb975..e75747d 100644
--- a/src/interfaces/flags/Attributes.php
+++ b/src/interfaces/flags/Attributes.php
@@ -11,7 +11,7 @@ interface Attributes
     /**
      * Return key-type pairs of the attributes
      *
-     * @return Array<int, string>
+     * @return array<int, string>
      */
     public function keys(): array;
 
@@ -21,7 +21,7 @@ public function keys(): array;
     public function get(string $key): bool | string | int | float | DateTime | array | null;
 
     /**
-     * @return Array<array-key, bool|string|int|float|DateTime|mixed[]|null>
+     * @return array<array-key, bool|string|int|float|DateTime|mixed[]|null>
      */
     public function toArray(): array;
 }
diff --git a/src/interfaces/flags/FlagMetadata.php b/src/interfaces/flags/FlagMetadata.php
index 554180d..5aac72e 100644
--- a/src/interfaces/flags/FlagMetadata.php
+++ b/src/interfaces/flags/FlagMetadata.php
@@ -13,14 +13,14 @@ interface FlagMetadata
     /**
      * Return key-type pairs of the attributes
      *
-     * @return Array<int, string>
+     * @return array<int, string>
      */
     public function keys(): array;
 
     public function get(string $key): bool | string | int | float | null;
 
     /**
-     * @return Array<array-key, bool|string|int|float|null>
+     * @return array<array-key, bool|string|int|float|null>
      */
     public function toArray(): array;
 }
diff --git a/src/interfaces/flags/FlagValueType.php b/src/interfaces/flags/FlagValueType.php
index 9108d77..1eea6ca 100644
--- a/src/interfaces/flags/FlagValueType.php
+++ b/src/interfaces/flags/FlagValueType.php
@@ -4,6 +4,14 @@
 
 namespace OpenFeature\interfaces\flags;
 
+use OpenFeature\interfaces\provider\ResolutionDetails;
+
+use function is_array;
+use function is_bool;
+use function is_float;
+use function is_int;
+use function is_string;
+
 enum FlagValueType: string
 {
     case String = 'STRING';
@@ -12,24 +20,28 @@ enum FlagValueType: string
     case Object = 'OBJECT';
     case Boolean = 'BOOLEAN';
 
-    /**
-     * @deprecated prefer enum value over const
-     */
-    public const STRING = 'STRING';
-    /**
-     * @deprecated prefer enum value over const
-     */
-    public const INTEGER = 'INTEGER';
-    /**
-     * @deprecated prefer enum value over const
-     */
-    public const FLOAT = 'FLOAT';
-    /**
-     * @deprecated prefer enum value over const
-     */
-    public const OBJECT = 'OBJECT';
-    /**
-     * @deprecated prefer enum value over const
-     */
-    public const BOOLEAN = 'BOOLEAN';
+    public static function tryFromResolutionDetails(ResolutionDetails $resolutionDetails): ?self
+    {
+        $value = $resolutionDetails->getValue();
+
+        return match (true) {
+            is_bool($value) => self::Boolean,
+            is_float($value) => self::Float,
+            is_int($value) => self::Integer,
+            is_string($value) => self::String,
+            is_array($value) => self::Object,
+            default => null,
+        };
+    }
+
+    /** @deprecated prefer enum value over const */
+    public const STRING = self::String;
+    /** @deprecated prefer enum value over const */
+    public const INTEGER = self::Integer;
+    /** @deprecated prefer enum value over const */
+    public const FLOAT = self::Float;
+    /** @deprecated prefer enum value over const */
+    public const OBJECT = self::Object;
+    /** @deprecated prefer enum value over const */
+    public const BOOLEAN = self::Boolean;
 }
diff --git a/src/interfaces/hooks/HooksAwareTrait.php b/src/interfaces/hooks/HooksAwareTrait.php
index 566de73..e1e978e 100644
--- a/src/interfaces/hooks/HooksAwareTrait.php
+++ b/src/interfaces/hooks/HooksAwareTrait.php
@@ -6,7 +6,7 @@
 
 trait HooksAwareTrait
 {
-    /** @var Array<Hook> $hooks */
+    /** @var array<Hook> $hooks */
     private array $hooks = [];
 
     /**
diff --git a/tests/unit/BaseHooksTest.php b/tests/unit/BaseHooksTest.php
index ac76629..9fe3d6e 100644
--- a/tests/unit/BaseHooksTest.php
+++ b/tests/unit/BaseHooksTest.php
@@ -50,7 +50,7 @@ public function finally(HookContext $context, HookHints $hints): void
     }
 
   /**
-   * @return Array<Array<mixed>>
+   * @return array<array<mixed>>
    */
     public function dataBooleanHook(): array
     {
@@ -94,7 +94,7 @@ public function finally(HookContext $context, HookHints $hints): void
     }
 
   /**
-   * @return Array<Array<mixed>>
+   * @return array<array<mixed>>
    */
     public function dataFloatHook(): array
     {
@@ -138,7 +138,7 @@ public function finally(HookContext $context, HookHints $hints): void
     }
 
   /**
-   * @return Array<Array<mixed>>
+   * @return array<array<mixed>>
    */
     public function dataIntegerHook(): array
     {
@@ -182,7 +182,7 @@ public function finally(HookContext $context, HookHints $hints): void
     }
 
   /**
-   * @return Array<Array<mixed>>
+   * @return array<array<mixed>>
    */
     public function dataObjectHook(): array
     {
@@ -226,7 +226,7 @@ public function finally(HookContext $context, HookHints $hints): void
     }
 
   /**
-   * @return Array<Array<mixed>>
+   * @return array<array<mixed>>
    */
     public function dataStringHook(): array
     {
diff --git a/tests/unit/StringHelperTest.php b/tests/unit/StringHelperTest.php
index 52e4954..86509cf 100644
--- a/tests/unit/StringHelperTest.php
+++ b/tests/unit/StringHelperTest.php
@@ -20,7 +20,7 @@ public function testCapitalize(string $input, string $expectedValue): void
     }
 
     /**
-     * @return Array<Array<string>>
+     * @return array<array<string>>
      */
     public function capitalizeData(): array
     {
@@ -46,7 +46,7 @@ public function testDecapitalize(string $input, string $expectedValue): void
     }
 
     /**
-     * @return Array<Array<string>>
+     * @return array<array<string>>
      */
     public function decapitalizeData(): array
     {