diff --git a/composer.json b/composer.json
index f3473f7..b372022 100644
--- a/composer.json
+++ b/composer.json
@@ -31,7 +31,7 @@
     "dealerdirect/phpcodesniffer-composer-installer": "^0.7",
     "phpcompatibility/phpcompatibility-wp": "*",
     "phpunit/phpunit": "^9.6",
-    "rector/rector": "^2.5",
+    "rector/rector": "2.7.0",
     "captainhook/captainhook": "^5.29",
     "captainhook/hook-installer": "^1.0"
   },
diff --git a/src/Cache/CacheManager.php b/src/Cache/CacheManager.php
index 143870e..f331279 100644
--- a/src/Cache/CacheManager.php
+++ b/src/Cache/CacheManager.php
@@ -34,9 +34,7 @@ public function store(?string $name = null): Repository
     {
         $name ??= $this->defaultStoreName();
 
-        if (!isset($this->repositories[$name])) {
-            $this->repositories[$name] = new Repository($this->makeStore($name));
-        }
+        $this->repositories[$name] ??= new Repository($this->makeStore($name));
 
         return $this->repositories[$name];
     }
diff --git a/src/Hooks/Hooks.php b/src/Hooks/Hooks.php
index 02c269e..c487759 100644
--- a/src/Hooks/Hooks.php
+++ b/src/Hooks/Hooks.php
@@ -20,9 +20,7 @@ final class Hooks
 
     public function __construct()
     {
-        if (!isset(self::$_hook)) {
-            self::$_hook = new HooksWrapper();
-        }
+        self::$_hook ??= new HooksWrapper();
     }
 
     public function __call(string $method, array $parameters)
diff --git a/src/Http/Detection/ClientIpResolver.php b/src/Http/Detection/ClientIpResolver.php
index c589049..0141c02 100644
--- a/src/Http/Detection/ClientIpResolver.php
+++ b/src/Http/Detection/ClientIpResolver.php
@@ -73,7 +73,7 @@ private static function isTrustedProxy(string $ip): bool
         return false;
     }
 
-    private static function isIpInRange(string $ip, $range)
+    private static function isIpInRange(string $ip, $range): bool
     {
         $range = trim((string) $range);
         if (!str_contains($range, '/')) {
diff --git a/src/Http/Response.php b/src/Http/Response.php
index 9d80924..384f580 100644
--- a/src/Http/Response.php
+++ b/src/Http/Response.php
@@ -254,9 +254,7 @@ private static function validateHeader($header, $value): array
 
     private static function current(): Response
     {
-        if (\is_null(self::$_current)) {
-            self::$_current = new self();
-        }
+        self::$_current ??= new self();
 
         return self::$_current;
     }
diff --git a/src/Http/Router/AjaxRouter.php b/src/Http/Router/AjaxRouter.php
index c1d5984..d363347 100644
--- a/src/Http/Router/AjaxRouter.php
+++ b/src/Http/Router/AjaxRouter.php
@@ -64,7 +64,7 @@ public function currentRoute()
         return $this->_router->getRegisteredRoute($this->currentRouteName());
     }
 
-    private function isRouteMatched(RouteRegister $route, string|array $requestPath)
+    private function isRouteMatched(RouteRegister $route, string|array $requestPath): bool
     {
         if ($route->getRoutePrefix() . $route->getPath() === $requestPath) {
             return true;
diff --git a/src/Http/Router/RouteBase.php b/src/Http/Router/RouteBase.php
index 5cc0c88..9094068 100644
--- a/src/Http/Router/RouteBase.php
+++ b/src/Http/Router/RouteBase.php
@@ -185,9 +185,7 @@ public function group(Closure $callback): self
      */
     public function getRouter()
     {
-        if (!isset($this->_router)) {
-            $this->_router = Router::instance();
-        }
+        $this->_router ??= Router::instance();
 
         return $this->_router;
     }
diff --git a/src/Http/Router/Router.php b/src/Http/Router/Router.php
index 5c3418e..2f5892f 100644
--- a/src/Http/Router/Router.php
+++ b/src/Http/Router/Router.php
@@ -77,9 +77,7 @@ public function getRegisteredRoutes(): array
     public static function instance($type = null, $namespace = null, $version = null)
     {
         if ($type === null) {
-            if (\is_null(self::$_instance)) {
-                self::$_instance = new self(RequestType::AJAX, $namespace, $version);
-            }
+            self::$_instance ??= new self(RequestType::AJAX, $namespace, $version);
 
             return self::$_instance;
         }
diff --git a/src/Settings/SettingsRepository.php b/src/Settings/SettingsRepository.php
index ecc7955..2f12c60 100644
--- a/src/Settings/SettingsRepository.php
+++ b/src/Settings/SettingsRepository.php
@@ -36,8 +36,12 @@ public function get(string $key, $default = null)
         }
 
         $field = $this->schema->field($key);
+        if ($field === null) {
+            return $default;
+        }
 
-        return $field !== null ? $field->default() : $default;
+        // A declared field's own default wins, even when it is null.
+        return $field->default();
     }
 
     /**
diff --git a/src/Shortcode/Shortcode.php b/src/Shortcode/Shortcode.php
index 83b780b..1ff10f2 100644
--- a/src/Shortcode/Shortcode.php
+++ b/src/Shortcode/Shortcode.php
@@ -19,9 +19,7 @@ final class Shortcode
 
     public function __construct()
     {
-        if (!isset(self::$_wrapper)) {
-            self::$_wrapper = new ShortcodeWrapper();
-        }
+        self::$_wrapper ??= new ShortcodeWrapper();
     }
 
     public function __call(string $method, array $parameters)
diff --git a/tests/Settings/SettingsRepositoryTest.php b/tests/Settings/SettingsRepositoryTest.php
index 0b210d6..b6c6d6e 100644
--- a/tests/Settings/SettingsRepositoryTest.php
+++ b/tests/Settings/SettingsRepositoryTest.php
@@ -36,6 +36,15 @@ public function testSetSaveReload(): void
         $this->assertFalse($fresh->get('logging_enabled'));
     }
 
+    public function testDeclaredNullDefaultWinsOverCallerFallback(): void
+    {
+        $schema = (new SettingsSchema())->add(SettingField::string('label', null));
+        $repo   = new SettingsRepository('demo_settings', $schema);
+
+        $this->assertNull($repo->get('label', 'fallback'));
+        $this->assertSame('fallback', $repo->get('undeclared', 'fallback'));
+    }
+
     public function testUnknownKeyRejected(): void
     {
         $this->expectException(InvalidArgumentException::class);