diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 000000000..15bd17299
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,8 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    labels:
+      - "CI"
diff --git a/.github/workflows/coding-standards.yml b/.github/workflows/coding-standards.yml
index 559e83399..d6d1396cf 100644
--- a/.github/workflows/coding-standards.yml
+++ b/.github/workflows/coding-standards.yml
@@ -12,6 +12,6 @@ on:
 jobs:
   coding-standards:
     name: "Coding Standards"
-    uses: "doctrine/.github/.github/workflows/coding-standards.yml@1.4.0"
+    uses: "doctrine/.github/.github/workflows/coding-standards.yml@5.1.0"
     with:
       php-version: "7.4"
diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 4b55228f3..ca371fd54 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -15,6 +15,8 @@ env:
 jobs:
   phpunit:
     name: "PHPUnit"
-    uses: "doctrine/.github/.github/workflows/continuous-integration.yml@1.1.1"
+    uses: "doctrine/.github/.github/workflows/continuous-integration.yml@5.1.0"
     with:
-      php-versions: '["7.1", "7.2", "7.3", "7.4", "8.0", "8.1", "8.2"]'
+      php-versions: '["7.1", "7.2", "7.3", "7.4", "8.0", "8.1", "8.2", "8.3", "8.4"]'
+    secrets:
+      CODECOV_TOKEN: "${{ secrets.CODECOV_TOKEN }}"
diff --git a/.github/workflows/release-on-milestone-closed.yml b/.github/workflows/release-on-milestone-closed.yml
index e7e127f4a..e193d87b6 100644
--- a/.github/workflows/release-on-milestone-closed.yml
+++ b/.github/workflows/release-on-milestone-closed.yml
@@ -8,7 +8,7 @@ on:
 jobs:
   release:
     name: "Git tag, release & create merge-up PR"
-    uses: "doctrine/.github/.github/workflows/release-on-milestone-closed.yml@1.4.1"
+    uses: "doctrine/.github/.github/workflows/release-on-milestone-closed.yml@5.1.0"
     secrets:
       GIT_AUTHOR_EMAIL: ${{ secrets.GIT_AUTHOR_EMAIL }}
       GIT_AUTHOR_NAME: ${{ secrets.GIT_AUTHOR_NAME }}
diff --git a/.github/workflows/static-analysis.yml b/.github/workflows/static-analysis.yml
index 9a911787d..a5f2b173f 100644
--- a/.github/workflows/static-analysis.yml
+++ b/.github/workflows/static-analysis.yml
@@ -12,6 +12,6 @@ on:
 jobs:
   static-analysis:
     name: "Static Analysis"
-    uses: "doctrine/.github/.github/workflows/static-analysis.yml@1.4.0"
+    uses: "doctrine/.github/.github/workflows/static-analysis.yml@5.1.0"
     with:
       php-version: "8.1"
diff --git a/src/Proxy/ProxyGenerator.php b/src/Proxy/ProxyGenerator.php
index ec6fb1004..9f35fd5a2 100644
--- a/src/Proxy/ProxyGenerator.php
+++ b/src/Proxy/ProxyGenerator.php
@@ -1282,7 +1282,6 @@ function (ReflectionType $intersectedType) use ($method, $parameter) {
         if (
             $type->allowsNull()
             && ! in_array($name, ['mixed', 'null'], true)
-            && ($parameter === null || ! $parameter->isDefaultValueAvailable() || $parameter->getDefaultValue() !== null)
         ) {
             $name = '?' . $name;
         }
diff --git a/tests/Common/Proxy/Php8UnionTypes.php b/tests/Common/Proxy/Php8UnionTypes.php
index ab5c391c8..c95412746 100644
--- a/tests/Common/Proxy/Php8UnionTypes.php
+++ b/tests/Common/Proxy/Php8UnionTypes.php
@@ -12,10 +12,16 @@ class Php8UnionTypes
 
     public function setValue(stdClass|array $value) : bool|float
     {
+        return true;
     }
 
     public function setNullableValue(stdClass|array|null $value) : bool|float|null
     {
+        return true;
     }
 
+    public function setNullableValueDefaultNull(stdClass|array|null $value = null) : bool|float|null
+    {
+        return true;
+    }
 }
diff --git a/tests/Common/Proxy/ProxyGeneratorTest.php b/tests/Common/Proxy/ProxyGeneratorTest.php
index 59c1eb3ef..168b3254b 100644
--- a/tests/Common/Proxy/ProxyGeneratorTest.php
+++ b/tests/Common/Proxy/ProxyGeneratorTest.php
@@ -180,7 +180,7 @@ public function testClassWithScalarTypeHintsOnProxiedMethods()
         self::assertEquals(1, substr_count($classCode, 'function combinationOfTypeHintsAndNormal(\stdClass $a, \Countable $b, $c, int $d)'));
         self::assertEquals(1, substr_count($classCode, 'function typeHintsWithVariadic(int ...$foo)'));
         self::assertEquals(1, substr_count($classCode, 'function withDefaultValue(int $foo = 123)'));
-        self::assertEquals(1, substr_count($classCode, 'function withDefaultValueNull(int $foo = NULL)'));
+        self::assertEquals(1, substr_count($classCode, 'function withDefaultValueNull(?int $foo = NULL)'));
     }
 
     public function testClassWithReturnTypesOnProxiedMethods()
@@ -220,8 +220,8 @@ public function testClassWithNullableTypeHintsOnProxiedMethods()
         self::assertEquals(1, substr_count($classCode, 'function nullableTypeHintObject(?\stdClass $param)'));
         self::assertEquals(1, substr_count($classCode, 'function nullableTypeHintSelf(?\\' . $className . ' $param)'));
         self::assertEquals(1, substr_count($classCode, 'function nullableTypeHintWithDefault(?int $param = 123)'));
-        self::assertEquals(1, substr_count($classCode, 'function nullableTypeHintWithDefaultNull(int $param = NULL)'));
-        self::assertEquals(1, substr_count($classCode, 'function notNullableTypeHintWithDefaultNull(int $param = NULL)'));
+        self::assertEquals(1, substr_count($classCode, 'function nullableTypeHintWithDefaultNull(?int $param = NULL)'));
+        self::assertEquals(1, substr_count($classCode, 'function notNullableTypeHintWithDefaultNull(?int $param = NULL)'));
     }
 
     public function testClassWithNullableReturnTypesOnProxiedMethods()
@@ -259,7 +259,7 @@ public function testClassWithNullableOptionalNonLastParameterOnProxiedMethods()
         }
 
         self::assertStringContainsString(
-            'public function midSignatureNullableParameter(\stdClass $param = NULL, $secondParam)',
+            'public function midSignatureNullableParameter(?\stdClass $param = NULL, $secondParam)',
             file_get_contents(__DIR__ . '/generated/__CG__DoctrineTestsCommonProxyNullableNonOptionalHintClass.php')
         );
 
@@ -287,7 +287,7 @@ public function testClassWithPhp71NullableOptionalNonLastParameterOnProxiedMetho
         }
 
         self::assertStringContainsString(
-            'public function midSignatureNullableParameter(string $param = NULL, $secondParam)',
+            'public function midSignatureNullableParameter(?string $param = NULL, $secondParam)',
             file_get_contents(__DIR__ . '/generated/__CG__DoctrineTestsCommonProxyPhp71NullableDefaultedNonOptionalHintClass.php'),
             'Signature allows nullable type, although explicit "?" marker isn\'t used in the proxy'
         );
@@ -460,6 +460,11 @@ public function testPhp8UnionTypes()
             'setNullableValue(\stdClass|array|null $value): float|bool|null',
             file_get_contents(__DIR__ . '/generated/__CG__DoctrineTestsCommonProxyPhp8UnionTypes.php')
         );
+
+        self::assertStringContainsString(
+            'setNullableValueDefaultNull(\stdClass|array|null $value = NULL): float|bool|null',
+            file_get_contents(__DIR__ . '/generated/__CG__DoctrineTestsCommonProxyPhp8UnionTypes.php')
+        );
     }
 
     /**