diff --git a/composer.json b/composer.json
index 0ab2ded..7d9ba70 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
     "require": {
         "php": "^8.1",
         "thecodingmachine/safe": "^2",
-        "webonyx/graphql-php": "^15.0"
+        "webonyx/graphql-php": "^15.4"
     },
     "require-dev": {
         "doctrine/coding-standard": "^12.0",
diff --git a/src/Builder/FieldBuilder.php b/src/Builder/FieldBuilder.php
index 1407387..9906855 100644
--- a/src/Builder/FieldBuilder.php
+++ b/src/Builder/FieldBuilder.php
@@ -63,8 +63,13 @@ public function setDescription(string $description): self
      *
      * @return $this
      */
-    public function addArgument(string $name, $type, string|null $description = null, mixed $defaultValue = null): self
-    {
+    public function addArgument(
+        string $name,
+        $type,
+        string|null $description = null,
+        mixed $defaultValue = null,
+        string|null $deprecationReason = null,
+    ): self {
         if ($this->args === null) {
             $this->args = [];
         }
@@ -80,6 +85,11 @@ public function addArgument(string $name, $type, string|null $description = null
             $value['defaultValue'] = $defaultValue;
         }
 
+        if ($deprecationReason !== null) {
+            /** @psalm-suppress MixedAssignment */
+            $value['deprecationReason'] = $deprecationReason;
+        }
+
         $this->args[$name] = $value;
 
         return $this;
diff --git a/src/Builder/InputFieldBuilder.php b/src/Builder/InputFieldBuilder.php
index bb08b64..f685db7 100644
--- a/src/Builder/InputFieldBuilder.php
+++ b/src/Builder/InputFieldBuilder.php
@@ -62,6 +62,14 @@ public function setDescription(string $description): self
         return $this;
     }
 
+    /** @return $this */
+    public function setDeprecationReason(string|null $deprecationReason): self
+    {
+        $this->deprecationReason = $deprecationReason;
+
+        return $this;
+    }
+
     /** @psalm-return InputObjectFieldConfig */
     public function build(): array
     {
@@ -73,7 +81,6 @@ public function build(): array
         ];
 
         $property = new ReflectionProperty($this, 'defaultValue');
-        $property->setAccessible(true);
         if ($property->isInitialized($this)) {
             /** @psalm-suppress MixedAssignment */
             $config['defaultValue'] = $this->defaultValue;
diff --git a/tests/Builder/FieldBuilderTest.php b/tests/Builder/FieldBuilderTest.php
index dbcff6c..81d2e20 100644
--- a/tests/Builder/FieldBuilderTest.php
+++ b/tests/Builder/FieldBuilderTest.php
@@ -18,7 +18,7 @@ public function testCreate(): void
             ->setDeprecationReason('Deprecated')
             ->setDescription('SomeDescription')
             ->setResolver(static fn (): string => 'Resolver result')
-            ->addArgument('arg1', Type::int(), 'Argument Description', 1)
+            ->addArgument('arg1', Type::int(), 'Argument Description', 1, 'Reason')
             ->build();
 
         self::assertSame('SomeField', $field['name']);
@@ -43,6 +43,7 @@ public function testCreate(): void
         self::assertIsArray($args['arg1']);
         self::assertSame(Type::int(), $args['arg1']['type']);
         self::assertSame('Argument Description', $args['arg1']['description']);
+        self::assertSame('Reason', $args['arg1']['deprecationReason']);
         self::assertSame(1, $args['arg1']['defaultValue']);
     }
 }
diff --git a/tests/Builder/InputFieldBuilderTest.php b/tests/Builder/InputFieldBuilderTest.php
index 3fb40f9..5030802 100644
--- a/tests/Builder/InputFieldBuilderTest.php
+++ b/tests/Builder/InputFieldBuilderTest.php
@@ -15,6 +15,7 @@ public function testCreate(): void
         $field = InputFieldBuilder::create('SomeField', Type::string())
             ->setDefaultValue(null)
             ->setDescription('SomeDescription')
+            ->setDeprecationReason('Reason')
             ->build();
 
         self::assertSame('SomeField', $field['name']);
@@ -22,6 +23,8 @@ public function testCreate(): void
         self::assertNull($field['defaultValue']);
         self::assertArrayHasKey('description', $field);
         self::assertSame('SomeDescription', $field['description']);
+        self::assertArrayHasKey('deprecationReason', $field);
+        self::assertSame('Reason', $field['deprecationReason']);
     }
 
     public function testCreateWithoutDefaultValue(): void