diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000000..aff5edb4b3
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,51 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - develop
+      - master
+      - main
+      - 'feat/**'
+      - 'fix/**'
+      - 'chore/**'
+  pull_request:
+    branches:
+      - develop
+      - master
+      - main
+
+jobs:
+  tests:
+    name: PHP ${{ matrix.php-version }}
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version:
+          - '8.2'
+          - '8.4'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          coverage: none
+          tools: composer:v2
+
+      - name: Validate composer.json
+        run: composer validate --no-check-publish --no-check-lock
+
+      - name: Install dependencies
+        run: composer update --prefer-dist --no-interaction --no-progress
+
+      - name: Lint PHP source
+        run: find src -name '*.php' -print0 | xargs -0 -n1 -P4 php -l
+
+      - name: Check autoloader
+        run: php -r "require 'vendor/autoload.php'; class_exists('Okta\\\\Client') or exit(1);"
diff --git a/composer.json b/composer.json
index 09a71339e2..e762f4e236 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,7 @@
         }
     ],
     "require": {
-        "php": "^7.3 | ^8.0",
+        "php": "^8.2 || ^8.4",
         "psr/http-message": "^1.0",
         "php-http/client-common": "^2.2",
         "php-http/httplug": "^2.2",
@@ -19,7 +19,7 @@
         "php-http/curl-client": "^2.2",
         "symfony/yaml": "^3.2|^4.3|^5.0",
         "nesbot/carbon": "^2.0",
-        "illuminate/collections": "^8.29.0",
+        "illuminate/collections": "^10.0 || ^11.0 || ^12.0",
         "guzzlehttp/psr7": "^1.7.0",
         "psr/cache": "^1.0",
         "league/flysystem-memory": "^1.0",
diff --git a/src/Cache/MemoryManager.php b/src/Cache/MemoryManager.php
index acbbd907c2..ac508de51c 100644
--- a/src/Cache/MemoryManager.php
+++ b/src/Cache/MemoryManager.php
@@ -25,7 +25,7 @@
 class MemoryManager extends CacheManager
 {
 
-    public function __construct(AbstractAdapter $adapter = null)
+    public function __construct(?AbstractAdapter $adapter = null)
     {
         if(null === $adapter) {
             $adapter = new MemoryAdapter();
diff --git a/src/Client.php b/src/Client.php
index 6705ee8ba5..5a542bb549 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -81,10 +81,10 @@ class Client
     public function __construct(
         string $token,
         string $organizationUrl,
-        HttpClient $httpClient = null,
+        ?HttpClient $httpClient = null,
         string $integrationUserAgent = null,
-        CacheManager $cacheManager = null,
-        AuthorizationMode $authorizationMode = null
+        ?CacheManager $cacheManager = null,
+        ?AuthorizationMode $authorizationMode = null
     ) {
         $this->token = $token;
         $this->organizationUrl = $organizationUrl;
diff --git a/src/DataStore/DefaultDataStore.php b/src/DataStore/DefaultDataStore.php
index 72d6e20b15..4eab1f8eef 100644
--- a/src/DataStore/DefaultDataStore.php
+++ b/src/DataStore/DefaultDataStore.php
@@ -89,7 +89,7 @@ class DefaultDataStore
      * @param HttpClient|NULL $httpClient
      * @param AuthorizationMode|NULL $authorizationMode
      */
-    public function __construct(string $token, string $organizationUrl, HttpClient $httpClient = null, AuthorizationMode $authorizationMode = null)
+    public function __construct(string $token, string $organizationUrl, ?HttpClient $httpClient = null, ?AuthorizationMode $authorizationMode = null)
     {
         $this->token = $token;
         $this->organizationUrl = $organizationUrl;
@@ -121,7 +121,7 @@ public function __construct(string $token, string $organizationUrl, HttpClient $
      * @param array          $options Any options you want to set.
      * @return object
      */
-    public function instantiate(string $class, \stdClass $properties = null, array $options = [])
+    public function instantiate(string $class, ?\stdClass $properties = null, array $options = [])
     {
         $propertiesArr = array($properties, $options);
 
diff --git a/src/Exceptions/ResourceException.php b/src/Exceptions/ResourceException.php
index 7069a9b386..4f79992194 100644
--- a/src/Exceptions/ResourceException.php
+++ b/src/Exceptions/ResourceException.php
@@ -23,7 +23,7 @@ class ResourceException extends GeneralException
 {
     private $error;
 
-    public function __construct(Error $error, Throwable $previous = null)
+    public function __construct(Error $error, ?Throwable $previous = null)
     {
         $this->error = $error;
         $message = $error->getErrorSummary() ?: '';
diff --git a/src/Okta.php b/src/Okta.php
index 1bc7acb988..f253cc50f4 100644
--- a/src/Okta.php
+++ b/src/Okta.php
@@ -30,7 +30,7 @@ class Okta
 
     const VERSION = '1.3.0';
 
-    public function __construct(Client $client = null, DefaultDataStore $dataStore = null)
+    public function __construct(?Client $client = null, ?DefaultDataStore $dataStore = null)
     {
         $this->client = $client ?: Client::getInstance();
         $this->dataStore = $dataStore ?: $this->client->getDataStore();
diff --git a/src/Resource/AbstractResource.php b/src/Resource/AbstractResource.php
index 7345329f8c..a4d88ca198 100644
--- a/src/Resource/AbstractResource.php
+++ b/src/Resource/AbstractResource.php
@@ -65,7 +65,7 @@ abstract class AbstractResource
      * @param \stdClass|NULL        $properties Properties for the resource.
      * @param array                 $options Options to use on the resource.
      */
-    public function __construct(DefaultDataStore $dataStore = null, \stdClass $properties = null, array $options = [])
+    public function __construct(?DefaultDataStore $dataStore = null, ?\stdClass $properties = null, array $options = [])
     {
         $this->dataStore = $dataStore ?: Client::getInstance()->getDataStore();
         $this->setProperties($properties);
@@ -90,7 +90,7 @@ public function getHref()
      * @param \stdClass|NULL $properties the properties to set.
      * @return self
      */
-    public function setProperties(\stdClass $properties = null): self
+    public function setProperties(?\stdClass $properties = null): self
     {
         $this->dirty = false;