diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 45dc50948..87dbf99fa 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [7.4, 8.0, 8.1, 8.2, 8.3]
+        php: [7.4, 8.0, 8.1, 8.2, 8.3, 8.4]
         experimental: [false]
         include:
           - php: 8.2
@@ -27,7 +27,12 @@ jobs:
           coverage: xdebug
 
       - name: Install dependencies with Composer
-        uses: ramsey/composer-install@v3
+        if: matrix.php < '8.4'
+        run: composer update --prefer-dist --no-progress --no-interaction --ansi
+
+      - name: Install dependencies with Composer
+        if: matrix.php >= '8.4'
+        run: composer update --prefer-dist --no-progress --no-interaction --ansi --ignore-platform-reqs
 
       - name: Coding standards
         if: matrix.analysis
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe2ab4ba5..52dbc9985 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,8 +6,9 @@
 
 ### Added
 
-### Removed
+- Add support for PHP 8.4
 
+### Removed
 
 ## 4.14.0 - 2024-06-13
 
diff --git a/Slim/Handlers/Strategies/RequestResponseNamedArgs.php b/Slim/Handlers/Strategies/RequestResponseNamedArgs.php
index f36059646..4153e113d 100644
--- a/Slim/Handlers/Strategies/RequestResponseNamedArgs.php
+++ b/Slim/Handlers/Strategies/RequestResponseNamedArgs.php
@@ -21,13 +21,6 @@
  */
 class RequestResponseNamedArgs implements InvocationStrategyInterface
 {
-    public function __construct()
-    {
-        if (PHP_VERSION_ID < 80000) {
-            throw new RuntimeException('Named arguments are only available for PHP >= 8.0.0');
-        }
-    }
-
     /**
      * Invoke a route callable with request, response and all route parameters
      * as individual arguments.
diff --git a/composer.json b/composer.json
index de7f66a66..a5057201d 100644
--- a/composer.json
+++ b/composer.json
@@ -43,7 +43,7 @@
         "wiki": "https://github.com/slimphp/Slim/wiki"
     },
     "require": {
-        "php": "^7.4 || ^8.0",
+        "php": "~7.4.0 || ~8.0.0 || ~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
         "ext-json": "*",
         "nikic/fast-route": "^1.3",
         "psr/container": "^1.0 || ^2.0",
@@ -69,7 +69,7 @@
         "slim/http": "^1.3",
         "slim/psr7": "^1.6",
         "squizlabs/php_codesniffer": "^3.10",
-        "vimeo/psalm": "^5.24"
+        "vimeo/psalm": "^5.26.1"
     },
     "autoload": {
         "psr-4": {
diff --git a/tests/Handlers/Strategies/RequestResponseNamedArgsTest.php b/tests/Handlers/Strategies/RequestResponseNamedArgsTest.php
index 11ff7b45b..fb7821bc6 100644
--- a/tests/Handlers/Strategies/RequestResponseNamedArgsTest.php
+++ b/tests/Handlers/Strategies/RequestResponseNamedArgsTest.php
@@ -12,7 +12,6 @@
 
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
-use RuntimeException;
 use Slim\Handlers\Strategies\RequestResponseNamedArgs;
 use Slim\Tests\TestCase;
 
@@ -29,16 +28,6 @@ public function setUp(): void
         $this->response = $this->createMock(ResponseInterface::class);
     }
 
-    public function testCreatingRequestResponseNamedArgsThrowsRuntimeExceptionForPHPOlderThan80()
-    {
-        if (PHP_VERSION_ID >= self::PHP_8_0_VERSION_ID) {
-            $this->markTestSkipped('Test only valid for PHP versions older than 8.0');
-        }
-
-        $this->expectException(RuntimeException::class);
-        new RequestResponseNamedArgs();
-    }
-
     public function testCallingWithEmptyArguments()
     {
         if (PHP_VERSION_ID < self::PHP_8_0_VERSION_ID) {
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 00d3896a4..dba4db5e5 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -24,7 +24,7 @@
 
             return connection_status();
         },
-        'header' => function (string $string, bool $replace = true, int $statusCode = null): void {
+        'header' => function (string $string, bool $replace = true, ?int $statusCode = null): void {
             HeaderStack::push(
                 [
                     'header' => $string,