diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 9c36647..b13df1d 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -21,6 +21,7 @@ jobs:
           - "8.1"
           - "8.2"
           - "8.3"
+          - "8.4"
 
     steps:
       - uses: actions/checkout@v3
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 46b0f47..b1a7563 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -1,5 +1,10 @@
 parameters:
     level: 5
+    reportUnmatchedIgnoredErrors: false
+
     paths:
         - src
         - tests
+
+    ignoreErrors:
+        - '#Attribute class Deprecated does not exist#'
diff --git a/src/Api/AbstractApi.php b/src/Api/AbstractApi.php
index d3ff630..a923eef 100644
--- a/src/Api/AbstractApi.php
+++ b/src/Api/AbstractApi.php
@@ -19,10 +19,10 @@ abstract class AbstractApi
     /** @var ResponseMediator */
     private $responseMediator;
 
-    public function __construct(Client $client, ResponseMediator $responseMediator = null)
+    public function __construct(Client $client, ?ResponseMediator $responseMediator = null)
     {
         $this->client = $client;
-        $this->responseMediator = $responseMediator ? $responseMediator : new ResponseMediator();
+        $this->responseMediator = $responseMediator ?: new ResponseMediator();
     }
 
     /**
diff --git a/src/Api/Credentials.php b/src/Api/Credentials.php
index d7f5a73..5d7c103 100644
--- a/src/Api/Credentials.php
+++ b/src/Api/Credentials.php
@@ -43,6 +43,7 @@ public function create($description, $type, $domain, $username, $credential)
     /**
      * @deprecated Use edit instead
      */
+    #[\Deprecated('Use Credentials::edit instead', '1.11.0')]
     public function update($credentialId, $type, $username, $credential)
     {
         return $this->edit($credentialId, $type, $username, $credential);
diff --git a/src/Api/Customers.php b/src/Api/Customers.php
index 27fbdbd..237d079 100644
--- a/src/Api/Customers.php
+++ b/src/Api/Customers.php
@@ -42,6 +42,7 @@ public function create($name, $accessToVersionControlSource = false, $urlName =
     /**
      * @deprecated Use edit instead
      */
+    #[\Deprecated('Use Customers::edit instead', '1.11.0')]
     public function update($customerIdOrUrlName, array $customer)
     {
         return $this->edit($customerIdOrUrlName, $customer);
@@ -80,6 +81,7 @@ public function showPackage($customerIdOrUrlName, $packageIdOrName)
     /**
      * @deprecated Use addOrEditPackages instead
      */
+    #[\Deprecated('Use Customers::addOrEditPackages instead', '1.11.0')]
     public function addOrUpdatePackages($customerIdOrUrlName, array $packages)
     {
         return $this->addOrEditPackages($customerIdOrUrlName, $packages);
@@ -99,6 +101,7 @@ public function addOrEditPackages($customerIdOrUrlName, array $packages)
     /**
      * @deprecated Use addOrEditPackages instead
      */
+    #[\Deprecated('Use Customers::addOrEditPackages instead', '1.11.0')]
     public function addPackages($customerIdOrUrlName, array $packages)
     {
         return $this->addOrEditPackages($customerIdOrUrlName, $packages);
diff --git a/src/Api/Packages.php b/src/Api/Packages.php
index 0660c95..6a1f1a0 100644
--- a/src/Api/Packages.php
+++ b/src/Api/Packages.php
@@ -35,11 +35,13 @@ class Packages extends AbstractApi
     /**
      * @deprecated Use Packages::ORIGIN_PUBLIC_MIRROR instead
      */
+    #[\Deprecated('Use Packages::ORIGIN_PUBLIC_MIRROR instead', '1.13.0')]
     const ORIGIN_PUBLIC_PROXY = self::ORIGIN_PUBLIC_MIRROR;
 
     /**
      * @deprecated Use Packages::ORIGIN_PRIVATE_MIRROR instead
      */
+    #[\Deprecated('Use Packages::ORIGIN_PRIVATE_MIRROR instead', '1.13.0')]
     const ORIGIN_PRIVATE_PROXY = self::ORIGIN_PRIVATE_MIRROR;
 
     const AVAILABLE_ORIGINS = [self::ORIGIN_PUBLIC_MIRROR, self::ORIGIN_PRIVATE_MIRROR, self::ORIGIN_PRIVATE, 'public-proxy', 'private-proxy'];
@@ -82,6 +84,7 @@ public function createArtifactPackage(array $artifactPackageFileIds, $defaultSub
     /**
      * @deprecated Use editVcsPackage instead
      */
+    #[\Deprecated('Use Packages::editVcsPackage instead', '1.11.0')]
     public function updateVcsPackage($packageName, $url, $credentialId = null)
     {
         return $this->editVcsPackage($packageName, $url, $credentialId);
@@ -104,6 +107,7 @@ public function editArtifactPackage($packageIdOrName, array $artifactPackageFile
     /**
      * @deprecated Use editCustomPackage instead
      */
+    #[\Deprecated('Use Packages::editCustomPackage instead', '1.11.0')]
     public function updateCustomPackage($packageName, $customJson, $credentialId = null)
     {
         return $this->editCustomPackage($packageName, $customJson, $credentialId);
diff --git a/src/Api/Subrepositories.php b/src/Api/Subrepositories.php
index 9185bad..075825b 100644
--- a/src/Api/Subrepositories.php
+++ b/src/Api/Subrepositories.php
@@ -41,6 +41,7 @@ public function listTeams($subrepositoryName)
     /**
      * @deprecated Use addOrEditTeams instead
      */
+    #[\Deprecated('Use Subrepositories::addOrEditTeams instead', '1.10.0')]
     public function addOrUpdateTeams($subrepositoryName, array $teams)
     {
         return $this->addOrEditTeams($subrepositoryName, $teams);
@@ -69,6 +70,7 @@ public function removeTeam($subrepositoryName, $teamId)
     /**
      * @deprecated use packages()->all()
      */
+    #[\Deprecated('Use Subrepositories::packages()->all() instead', '1.16.1')]
     public function listPackages($subrepositoryName)
     {
         return $this->packages()->all($subrepositoryName);
diff --git a/src/Client.php b/src/Client.php
index bd25209..381423a 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -25,7 +25,7 @@ class Client
     private $responseMediator;
 
     /** @param string $privatePackagistUrl */
-    public function __construct(HttpPluginClientBuilder $httpClientBuilder = null, $privatePackagistUrl = null, ResponseMediator $responseMediator = null)
+    public function __construct(?HttpPluginClientBuilder $httpClientBuilder = null, $privatePackagistUrl = null, ?ResponseMediator $responseMediator = null)
     {
         $this->httpClientBuilder = $builder = $httpClientBuilder ?: new HttpPluginClientBuilder();
         $privatePackagistUrl = $privatePackagistUrl ? : 'https://packagist.com';
@@ -48,8 +48,12 @@ public function __construct(HttpPluginClientBuilder $httpClientBuilder = null, $
      * @param string $key
      * @param string $secret
      */
-    public function authenticate($key, $secret)
-    {
+    public function authenticate(
+        #[\SensitiveParameter]
+        $key,
+        #[\SensitiveParameter]
+        $secret
+    ) {
         $this->httpClientBuilder->removePlugin(RequestSignature::class);
         $this->httpClientBuilder->addPlugin(new RequestSignature($key, $secret));
     }
@@ -72,6 +76,7 @@ public function customers()
     /**
      * @deprecated Use Client::subrepositories instead
      */
+    #[\Deprecated('Use Client::subrepositories instead', '1.16.1')]
     public function projects()
     {
         return new Api\Subrepositories($this, $this->responseMediator);
diff --git a/src/Exception/HttpTransportException.php b/src/Exception/HttpTransportException.php
index 52c3546..2f5e423 100644
--- a/src/Exception/HttpTransportException.php
+++ b/src/Exception/HttpTransportException.php
@@ -15,7 +15,7 @@ class HttpTransportException extends RuntimeException
 {
     private $requestUri;
 
-    public function __construct($message = "", $code = 0, $requestUri = "", Throwable $previous = null)
+    public function __construct($message = "", $code = 0, $requestUri = "", ?Throwable $previous = null)
     {
         $this->requestUri = $requestUri;
         parent::__construct($message, $code, $previous);
diff --git a/src/HttpClient/Plugin/ExceptionThrower.php b/src/HttpClient/Plugin/ExceptionThrower.php
index 1dd1ae9..96180b6 100644
--- a/src/HttpClient/Plugin/ExceptionThrower.php
+++ b/src/HttpClient/Plugin/ExceptionThrower.php
@@ -24,9 +24,9 @@ class ExceptionThrower implements Plugin
     /** @var ResponseMediator */
     private $responseMediator;
 
-    public function __construct(ResponseMediator $responseMediator = null)
+    public function __construct(?ResponseMediator $responseMediator = null)
     {
-        $this->responseMediator = $responseMediator ? $responseMediator : new ResponseMediator();
+        $this->responseMediator = $responseMediator ? : new ResponseMediator();
     }
 
     protected function doHandleRequest(RequestInterface $request, callable $next, callable $first)
diff --git a/src/HttpClient/Plugin/RequestSignature.php b/src/HttpClient/Plugin/RequestSignature.php
index 3988c30..c313778 100644
--- a/src/HttpClient/Plugin/RequestSignature.php
+++ b/src/HttpClient/Plugin/RequestSignature.php
@@ -25,8 +25,12 @@ class RequestSignature implements Plugin
      * @param string $key
      * @param string $secret
      */
-    public function __construct($key, $secret)
-    {
+    public function __construct(
+        #[\SensitiveParameter]
+        $key,
+        #[\SensitiveParameter]
+        $secret
+    ) {
         if (!$key || !$secret) {
             throw new \InvalidArgumentException('$key and $secret must be set');
         }
diff --git a/src/WebhookSignature.php b/src/WebhookSignature.php
index b1782b6..5434183 100644
--- a/src/WebhookSignature.php
+++ b/src/WebhookSignature.php
@@ -14,8 +14,10 @@ class WebhookSignature
     /** @var string */
     private $secret;
 
-    public function __construct($secret)
-    {
+    public function __construct(
+        #[\SensitiveParameter]
+        $secret
+    ) {
         $this->secret = $secret;
     }