diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 12a8537..ad50a8a 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        php: [8.2, 8.1, 8.0]
+        php: [8.3, 8.2, 8.1]
         laravel: ['8.*', '9.*', '10.*', '11.*']
         include:
           - laravel: 10.*
@@ -25,16 +25,8 @@ jobs:
           - laravel: 11.*
             testbench: 9.*
         exclude:
-          - laravel: 10.*
-            php: 8.0
-          - laravel: 10.*
-            php: 7.4
-          - laravel: 9.*
-            php: 7.4
           - laravel: 11.*
             php: 8.1
-          - laravel: 11.*
-            php: 8.0
 
     steps:
       - name: Checkout code
diff --git a/.gitignore b/.gitignore
index 3f0a634..74b638a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 /vendor
 build
+.phpunit.result.cache
 composer.phar
 composer.lock
diff --git a/composer.json b/composer.json
index 3be3655..6e60f0e 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": "^8.0",
+        "php": "^8.1",
         "guzzlehttp/guzzle": "^7.0.1",
         "illuminate/notifications": "^8.0 || ^9.0 || ^10.0 || ^11.0",
         "illuminate/support": "^8.0 || ^9.0 || ^10.0 || ^11.0"
diff --git a/src/Exceptions/CouldNotSendNotification.php b/src/Exceptions/CouldNotSendNotification.php
index 93ba3bd..8fbca37 100644
--- a/src/Exceptions/CouldNotSendNotification.php
+++ b/src/Exceptions/CouldNotSendNotification.php
@@ -3,15 +3,16 @@
 namespace NotificationChannels\Pushover\Exceptions;
 
 use Exception;
+use Illuminate\Notifications\AnonymousNotifiable;
 use Psr\Http\Message\ResponseInterface;
 
 class CouldNotSendNotification extends Exception
 {
-    public static function serviceRespondedWithAnError(ResponseInterface $response, $notifiable)
+    public static function serviceRespondedWithAnError(ResponseInterface $response, $notifiable): static
     {
         $statusCode = $response->getStatusCode();
 
-        $result = json_decode($response->getBody());
+        $result = json_decode($response->getBody()->getContents());
 
         $exceptionMessage = sprintf(
             "Pushover responded with an error (%s) for notifiable '%s' with id '%s'",
@@ -30,8 +31,12 @@ public static function serviceRespondedWithAnError(ResponseInterface $response,
         return new static($exceptionMessage, $statusCode);
     }
 
-    public static function pushoverKeyHasWrongLength($notifiable)
+    public static function pushoverKeyHasWrongLength($notifiable): static
     {
+        if ($notifiable instanceof AnonymousNotifiable) {
+            return new static('Pushover key has wrong length. It needs to be 30 characters long.');
+        }
+
         $exceptionMessage = sprintf(
             "Pushover key has wrong length for notifiable '%s' with id '%s'. It needs to be 30 characters long.",
             get_class($notifiable),
diff --git a/src/Exceptions/ServiceCommunicationError.php b/src/Exceptions/ServiceCommunicationError.php
index 0e33c22..59ec424 100644
--- a/src/Exceptions/ServiceCommunicationError.php
+++ b/src/Exceptions/ServiceCommunicationError.php
@@ -6,7 +6,7 @@
 
 class ServiceCommunicationError extends Exception
 {
-    public static function communicationFailed(Exception $exception)
+    public static function communicationFailed(Exception $exception): static
     {
         return new static("The communication with Pushover failed because `{$exception->getCode()} - {$exception->getMessage()}`");
     }
diff --git a/src/Pushover.php b/src/Pushover.php
index 50a1b18..4afca02 100644
--- a/src/Pushover.php
+++ b/src/Pushover.php
@@ -4,9 +4,11 @@
 
 use Exception;
 use GuzzleHttp\Client as HttpClient;
+use GuzzleHttp\Exception\GuzzleException;
 use GuzzleHttp\Exception\RequestException;
 use NotificationChannels\Pushover\Exceptions\CouldNotSendNotification;
 use NotificationChannels\Pushover\Exceptions\ServiceCommunicationError;
+use Psr\Http\Message\ResponseInterface;
 
 class Pushover
 {
@@ -22,27 +24,27 @@ class Pushover
      *
      * @var string
      */
-    protected $pushoverApiUrl = 'https://api.pushover.net/1/messages.json';
+    protected string $pushoverApiUrl = 'https://api.pushover.net/1/messages.json';
 
     /**
      * The HTTP client instance.
      *
-     * @var \GuzzleHttp\Client
+     * @var HttpClient
      */
-    protected $http;
+    protected HttpClient $http;
 
     /**
      * Pushover App Token.
      *
      * @var string
      */
-    protected $token;
+    protected string $token;
 
     /**
-     * @param  HttpClient  $http
-     * @param  string  $token
+     * @param HttpClient $http
+     * @param string     $token
      */
-    public function __construct(HttpClient $http, $token)
+    public function __construct(HttpClient $http, string $token)
     {
         $this->http = $http;
 
@@ -54,13 +56,15 @@ public function __construct(HttpClient $http, $token)
      *
      * @link  https://pushover.net/api
      *
-     * @param  array  $params
+     * @param array $params
      * @param mixed $notifiable
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
      *
      * @throws CouldNotSendNotification
+     * @throws ServiceCommunicationError
+     * @throws GuzzleException
      */
-    public function send($params, $notifiable)
+    public function send(array $params, mixed $notifiable): ResponseInterface
     {
         try {
             $multipart = [];
@@ -68,7 +72,7 @@ public function send($params, $notifiable)
             foreach ($this->paramsWithToken($params) as $name => $contents) {
                 if ($name !== 'image') {
                     $multipart[] = [
-                        'name'     => $name,
+                        'name' => $name,
                         'contents' => $contents,
                     ];
                 } else {
@@ -80,6 +84,7 @@ public function send($params, $notifiable)
                 }
             }
 
+            //dd($multipart);
             return $this->http->post(
                 $this->pushoverApiUrl,
                 [
@@ -101,10 +106,10 @@ public function send($params, $notifiable)
     /**
      * Merge token into parameters array, unless it has been set on the PushoverReceiver.
      *
-     * @param  array  $params
+     * @param array $params
      * @return array
      */
-    protected function paramsWithToken($params)
+    protected function paramsWithToken(array $params): array
     {
         return array_merge([
             'token' => $this->token,
@@ -119,9 +124,14 @@ protected function paramsWithToken($params)
      *
      * @param $file
      * @return array|null
+     * @throws GuzzleException
      */
     private function getImageData($file): ?array
     {
+        if (empty($file)) {
+            return null;
+        }
+
         try {
             // check if $file is not too big
             if (is_file($file) && is_readable($file)) {
@@ -141,7 +151,7 @@ private function getImageData($file): ?array
                 }
 
                 // some servers may not return the "Content-Length" header
-                $fileSizeChecked = (bool) $contentLength;
+                $fileSizeChecked = (bool)$contentLength;
             }
 
             // check if $file is an image
@@ -153,7 +163,7 @@ private function getImageData($file): ?array
 
             $contents = file_get_contents($file);
             // if not checked before, finally check the file size after reading it
-            if (! $fileSizeChecked && strlen($contents) > self::IMAGE_SIZE_LIMIT) {
+            if (!$fileSizeChecked && strlen($contents) > self::IMAGE_SIZE_LIMIT) {
                 return null;
             }
         } catch (Exception $exception) {
@@ -162,10 +172,10 @@ private function getImageData($file): ?array
 
         return [
             // name of the field holding the image must be 'attachment' (https://pushover.net/api#attachments)
-            'name'     => 'attachment',
+            'name' => 'attachment',
             'contents' => $contents,
             'filename' => basename($file),
-            'headers'  => [
+            'headers' => [
                 'Content-Type' => $contentType,
             ],
         ];
diff --git a/src/PushoverChannel.php b/src/PushoverChannel.php
index d3359dc..e346556 100644
--- a/src/PushoverChannel.php
+++ b/src/PushoverChannel.php
@@ -2,6 +2,7 @@
 
 namespace NotificationChannels\Pushover;
 
+use GuzzleHttp\Exception\GuzzleException;
 use Illuminate\Contracts\Events\Dispatcher;
 use Illuminate\Notifications\Events\NotificationFailed;
 use Illuminate\Notifications\Notification;
@@ -10,16 +11,15 @@
 
 class PushoverChannel
 {
-    /** @var Pushover */
-    protected $pushover;
+    protected Pushover $pushover;
 
-    /** @var Dispatcher */
-    protected $events;
+    protected Dispatcher $events;
 
     /**
      * Create a new Pushover channel instance.
      *
-     * @param  Pushover  $pushover
+     * @param Pushover   $pushover
+     * @param Dispatcher $events
      */
     public function __construct(Pushover $pushover, Dispatcher $events)
     {
@@ -30,12 +30,13 @@ public function __construct(Pushover $pushover, Dispatcher $events)
     /**
      * Send the given notification.
      *
-     * @param  mixed  $notifiable
-     * @param  \Illuminate\Notifications\Notification  $notification
+     * @param mixed        $notifiable
+     * @param Notification $notification
      *
-     * @throws \NotificationChannels\Pushover\Exceptions\CouldNotSendNotification
+     * @throws CouldNotSendNotification
+     * @throws GuzzleException
      */
-    public function send($notifiable, Notification $notification)
+    public function send(mixed $notifiable, Notification $notification): void
     {
         if (! $pushoverReceiver = $notifiable->routeNotificationFor('pushover')) {
             return;
@@ -63,7 +64,7 @@ public function send($notifiable, Notification $notification)
         }
     }
 
-    protected function fireFailedEvent($notifiable, $notification, $message)
+    protected function fireFailedEvent($notifiable, $notification, $message): void
     {
         $this->events->dispatch(
             new NotificationFailed($notifiable, $notification, 'pushover', [$message])
diff --git a/src/PushoverMessage.php b/src/PushoverMessage.php
index 4ff3065..eaae8d1 100644
--- a/src/PushoverMessage.php
+++ b/src/PushoverMessage.php
@@ -12,111 +12,109 @@ class PushoverMessage
      *
      * @var string
      */
-    public $content;
+    public string $content;
 
     /**
      * The format of the message.
      *
-     * Either "plain", "html" or "monospace".
-     *
-     * @var string
+     * @var int
      */
-    public $format = self::FORMAT_PLAIN;
+    public int $format = self::FORMAT_PLAIN;
 
     /**
      * The (optional) title of the message.
      *
      * @var string
      */
-    public $title;
+    public string $title;
 
     /**
      * The (optional) timestamp of the message.
      *
      * @var int
      */
-    public $timestamp;
+    public int $timestamp;
 
     /**
      * The (optional) priority of the message.
      *
      * @var int
      */
-    public $priority;
+    public int $priority;
 
     /**
      * The (optional) timeout between retries when sending a message
      * with an emergency priority. The timeout is in seconds.
      *
-     * @var int
+     * @var int|null
      */
-    public $retry;
+    public int|null $retry;
 
     /**
      * The (optional) expire time of a message with an emergency priority.
      * The expire time is in seconds.
      *
-     * @var int
+     * @var int|null
      */
-    public $expire;
+    public int|null $expire;
 
     /**
      * The (optional) supplementary url of the message.
      *
      * @var string
      */
-    public $url;
+    public string $url;
 
     /**
      * The (optional) supplementary url title of the message.
      *
      * @var string
      */
-    public $urlTitle;
+    public string $urlTitle;
 
     /**
      * The (optional) sound of the message.
      *
      * @var string
      */
-    public $sound;
+    public string $sound;
 
     /**
      * The (optional) image to be attached to the message.
      *
      * @var string
      */
-    public $image;
+    public string $image = '';
 
     /**
      * Message formats.
      */
-    const FORMAT_PLAIN = 0;
-    const FORMAT_HTML = 1;
-    const FORMAT_MONOSPACE = 2;
+    public const FORMAT_PLAIN = 0;
+    public const FORMAT_HTML = 1;
+    public const FORMAT_MONOSPACE = 2;
 
     /**
      * Message priorities.
      */
-    const LOWEST_PRIORITY = -2;
-    const LOW_PRIORITY = -1;
-    const NORMAL_PRIORITY = 0;
-    const HIGH_PRIORITY = 1;
-    const EMERGENCY_PRIORITY = 2;
+    public const LOWEST_PRIORITY = -2;
+    public const LOW_PRIORITY = -1;
+    public const NORMAL_PRIORITY = 0;
+    public const HIGH_PRIORITY = 1;
+    public const EMERGENCY_PRIORITY = 2;
 
     /**
-     * @param  string  $content
+     * @param string $content
      * @return static
      */
-    public static function create($content = '')
+    public static function create(string $content = ''): static
     {
         return new static($content);
     }
 
     /**
-     * @param  string  $content
+     * @param string $content
      */
-    public function __construct($content = '')
+    public function __construct(string $content = '')
     {
         $this->content = $content;
     }
@@ -124,10 +122,10 @@ public function __construct($content = '')
     /**
      * Set the content of the Pushover message.
      *
-     * @param  string  $content
+     * @param string $content
      * @return $this
      */
-    public function content($content)
+    public function content(string $content): static
     {
         $this->content = $content;
 
@@ -139,7 +137,7 @@ public function content($content)
      *
      * @return $this
      */
-    public function plain()
+    public function plain(): static
     {
         $this->format = static::FORMAT_PLAIN;
 
@@ -151,7 +149,7 @@ public function plain()
      *
      * @return $this
      */
-    public function html()
+    public function html(): static
     {
         $this->format = static::FORMAT_HTML;
 
@@ -163,7 +161,7 @@ public function html()
      *
      * @return $this
      */
-    public function monospace()
+    public function monospace(): static
     {
         $this->format = self::FORMAT_MONOSPACE;
 
@@ -173,10 +171,10 @@ public function monospace()
     /**
      * Set the title of the Pushover message.
      *
-     * @param  string  $title
+     * @param string $title
      * @return $this
      */
-    public function title($title)
+    public function title(string $title): static
     {
         $this->title = $title;
 
@@ -186,13 +184,13 @@ public function title($title)
     /**
      * Set the time of the Pushover message.
      *
-     * @param  Carbon|int  $time
+     * @param int|Carbon $time
      * @return $this
      */
-    public function time($time)
+    public function time(int|Carbon $time): static
     {
         if ($time instanceof Carbon) {
-            $time = $time->timestamp;
+            $time = (int)$time->timestamp;
         }
 
         $this->timestamp = $time;
@@ -203,11 +201,11 @@ public function time($time)
     /**
      * Set a supplementary url for the Pushover message.
      *
-     * @param  string  $url
-     * @param  string  $title
+     * @param string $url
+     * @param string $title
      * @return $this
      */
-    public function url($url, $title = null)
+    public function url(string $url, string $title = ''): static
     {
         $this->url = $url;
         $this->urlTitle = $title;
@@ -218,10 +216,10 @@ public function url($url, $title = null)
     /**
      * Set the sound of the Pushover message.
      *
-     * @param  string  $sound
+     * @param string $sound
      * @return $this
      */
-    public function sound($sound)
+    public function sound(string $sound): static
     {
         $this->sound = $sound;
 
@@ -231,10 +229,10 @@ public function sound($sound)
     /**
      * Set the image for attaching to the Pushover message. Either full or relative server path or a URL.
      *
-     * @param  string  $image
+     * @param string $image
      * @return $this
      */
-    public function image($image)
+    public function image(string $image): static
     {
         $this->image = $image;
 
@@ -245,12 +243,13 @@ public function image($image)
      * Set the priority of the Pushover message.
      * Retry and expire are mandatory when setting the priority to emergency.
      *
-     * @param  int  $priority
-     * @param  int  $retryTimeout
-     * @param  int  $expireAfter
+     * @param int      $priority
+     * @param int|null $retryTimeout
+     * @param int|null $expireAfter
      * @return $this
+     * @throws EmergencyNotificationRequiresRetryAndExpire
      */
-    public function priority($priority, $retryTimeout = null, $expireAfter = null)
+    public function priority(int $priority, int|null $retryTimeout = null, int|null $expireAfter = null): static
     {
         $this->noEmergencyWithoutRetryOrExpire($priority, $retryTimeout, $expireAfter);
 
@@ -265,8 +264,9 @@ public function priority($priority, $retryTimeout = null, $expireAfter = null)
      * Set the priority of the Pushover message to the lowest priority.
      *
      * @return $this
+     * @throws EmergencyNotificationRequiresRetryAndExpire
      */
-    public function lowestPriority()
+    public function lowestPriority(): static
     {
         return $this->priority(self::LOWEST_PRIORITY);
     }
@@ -275,8 +275,9 @@ public function lowestPriority()
      * Set the priority of the Pushover message to low.
      *
      * @return $this
+     * @throws EmergencyNotificationRequiresRetryAndExpire
      */
-    public function lowPriority()
+    public function lowPriority(): static
     {
         return $this->priority(self::LOW_PRIORITY);
     }
@@ -285,8 +286,9 @@ public function lowPriority()
      * Set the priority of the Pushover message to normal.
      *
      * @return $this
+     * @throws EmergencyNotificationRequiresRetryAndExpire
      */
-    public function normalPriority()
+    public function normalPriority(): static
     {
         return $this->priority(self::NORMAL_PRIORITY);
     }
@@ -295,8 +297,9 @@ public function normalPriority()
      * Set the priority of the Pushover message to high.
      *
      * @return $this
+     * @throws EmergencyNotificationRequiresRetryAndExpire
      */
-    public function highPriority()
+    public function highPriority(): static
     {
         return $this->priority(self::HIGH_PRIORITY);
     }
@@ -305,11 +308,12 @@ public function highPriority()
      * Set the priority of the Pushover message to emergency.
      * Retry and expire are mandatory when setting the priority to emergency.
      *
-     * @param  int  $retryTimeout
-     * @param  int  $expireAfter
+     * @param int $retryTimeout
+     * @param int $expireAfter
      * @return $this
+     * @throws EmergencyNotificationRequiresRetryAndExpire
      */
-    public function emergencyPriority($retryTimeout, $expireAfter)
+    public function emergencyPriority(int $retryTimeout, int $expireAfter): static
     {
         return $this->priority(self::EMERGENCY_PRIORITY, $retryTimeout, $expireAfter);
     }
@@ -319,7 +323,7 @@ public function emergencyPriority($retryTimeout, $expireAfter)
      *
      * @return array
      */
-    public function toArray()
+    public function toArray(): array
     {
         return [
             'message' => $this->content,
@@ -340,15 +344,15 @@ public function toArray()
     /**
      * Ensure an emergency message has an retry and expiry time.
      *
-     * @param  int  $priority
-     * @param  int  $retry
-     * @param  int  $expire
+     * @param int      $priority
+     * @param int|null $retry
+     * @param int|null $expire
      *
      * @throws EmergencyNotificationRequiresRetryAndExpire
      */
-    protected function noEmergencyWithoutRetryOrExpire($priority, $retry, $expire)
+    protected function noEmergencyWithoutRetryOrExpire(int $priority, int|null $retry, int|null $expire): void
     {
-        if ($priority == self::EMERGENCY_PRIORITY && (! isset($retry) || ! isset($expire))) {
+        if ($priority === self::EMERGENCY_PRIORITY && ($retry === null || $expire === null)) {
             throw new EmergencyNotificationRequiresRetryAndExpire();
         }
     }
diff --git a/src/PushoverReceiver.php b/src/PushoverReceiver.php
index f228a41..83472f8 100644
--- a/src/PushoverReceiver.php
+++ b/src/PushoverReceiver.php
@@ -4,16 +4,16 @@
 
 class PushoverReceiver
 {
-    protected $key;
-    protected $token;
-    protected $devices = [];
+    protected string $key;
+    protected string|null $token = null;
+    protected array $devices = [];
 
     /**
      * PushoverReceiver constructor.
      *
-     * @param  $key  User or group key.
+     * @param string $key User or group key.
      */
-    protected function __construct($key)
+    protected function __construct(string $key)
     {
         $this->key = $key;
     }
@@ -21,10 +21,10 @@ protected function __construct($key)
     /**
      * Create new Pushover receiver with an user key.
      *
-     * @param  $userKey  Pushover user key.
+     * @param string $userKey Pushover user key.
      * @return PushoverReceiver
      */
-    public static function withUserKey($userKey)
+    public static function withUserKey(string $userKey): PushoverReceiver
     {
         return new static($userKey);
     }
@@ -32,10 +32,10 @@ public static function withUserKey($userKey)
     /**
      * Create new Pushover receiver with a group key.
      *
-     * @param  $groupKey  Pushover group key.
+     * @param string $groupKey Pushover group key.
      * @return PushoverReceiver
      */
-    public static function withGroupKey($groupKey)
+    public static function withGroupKey(string $groupKey): PushoverReceiver
     {
         // This has exactly the same behaviour as an user key, so we
         // will use the same factory method as for the user key.
@@ -45,18 +45,17 @@ public static function withGroupKey($groupKey)
     /**
      * Send the message to a specific device.
      *
-     * @param  array|string  $device
+     * @param array|string $device
      * @return PushoverReceiver
      */
-    public function toDevice($device)
+    public function toDevice(array|string $device): static
     {
         if (is_array($device)) {
             $this->devices = array_merge($device, $this->devices);
-
             return $this;
         }
-        $this->devices[] = $device;
 
+        $this->devices[] = $device;
         return $this;
     }
 
@@ -66,7 +65,7 @@ public function toDevice($device)
      * @param $token
      * @return PushoverReceiver
      */
-    public function withApplicationToken($token)
+    public function withApplicationToken($token): static
     {
         $this->token = $token;
 
@@ -78,7 +77,7 @@ public function withApplicationToken($token)
      *
      * @return array
      */
-    public function toArray()
+    public function toArray(): array
     {
         return array_merge([
             'user' => $this->key,
diff --git a/src/PushoverServiceProvider.php b/src/PushoverServiceProvider.php
index 4757648..1d83106 100644
--- a/src/PushoverServiceProvider.php
+++ b/src/PushoverServiceProvider.php
@@ -10,7 +10,7 @@ class PushoverServiceProvider extends ServiceProvider
     /**
      * Bootstrap the application services.
      */
-    public function boot()
+    public function boot(): void
     {
         $this->app->when(PushoverChannel::class)
             ->needs(Pushover::class)
@@ -18,11 +18,4 @@ public function boot()
                 return new Pushover(new HttpClient(), config('services.pushover.token'));
             });
     }
-
-    /**
-     * Register the application services.
-     */
-    public function register()
-    {
-    }
 }
diff --git a/tests/IntegrationTest.php b/tests/IntegrationTest.php
index 9416812..1183677 100644
--- a/tests/IntegrationTest.php
+++ b/tests/IntegrationTest.php
@@ -34,7 +34,7 @@ public function setUp(): void
     }
 
     /** @test */
-    public function it_can_send_a_pushover_notification_with_a_global_token()
+    public function it_can_send_a_pushover_notification_with_a_global_token(): void
     {
         $message = (new PushoverMessage('Message text'))
             ->title('Message title')
@@ -45,19 +45,19 @@ public function it_can_send_a_pushover_notification_with_a_global_token()
 
         $this->requestWillBeSentToPushoverWith([
             'token' => 'global-application-token',
-            'user' => 'pushover-key',
-            'device' => 'iphone,desktop',
             'message' => 'Message text',
             'title' => 'Message title',
-            'priority' => 2,
-            'retry' => 60,
-            'expire' => 600,
             'timestamp' => 123456789,
-            'sound' => 'boing',
+            'priority' => 2,
             'url' => 'http://example.com',
             'url_title' => 'Example Website',
+            'sound' => 'boing',
+            'retry' => 60,
+            'expire' => 600,
             'html' => false,
             'monospace' => false,
+            'user' => 'pushover-key-30characters-long',
+            'device' => 'iphone,desktop',
         ]);
 
         $pushover = new Pushover($this->guzzleClient, 'global-application-token');
@@ -70,7 +70,7 @@ public function it_can_send_a_pushover_notification_with_a_global_token()
     }
 
     /** @test */
-    public function it_can_send_a_pushover_notification_with_an_overridden_token()
+    public function it_can_send_a_pushover_notification_with_an_overridden_token(): void
     {
         $message = (new PushoverMessage('Message <b>text</b>'))
             ->html()
@@ -82,19 +82,19 @@ public function it_can_send_a_pushover_notification_with_an_overridden_token()
 
         $this->requestWillBeSentToPushoverWith([
             'token' => 'overridden-application-token',
-            'user' => 'pushover-key',
-            'device' => 'iphone,desktop',
             'message' => 'Message <b>text</b>',
             'title' => 'Message title',
-            'priority' => 2,
-            'retry' => 60,
-            'expire' => 600,
             'timestamp' => 123456789,
-            'sound' => 'boing',
+            'priority' => 2,
             'url' => 'http://example.com',
             'url_title' => 'Example Website',
+            'sound' => 'boing',
+            'retry' => 60,
+            'expire' => 600,
             'html' => true,
             'monospace' => false,
+            'user' => 'pushover-key-30characters-long',
+            'device' => 'iphone,desktop',
         ]);
 
         $pushover = new Pushover($this->guzzleClient, 'global-application-token');
@@ -106,19 +106,25 @@ public function it_can_send_a_pushover_notification_with_an_overridden_token()
         $channel->send(new NotifiableWithPushoverReceiverWithToken(), $this->notification);
     }
 
-    protected function requestWillBeSentToPushoverWith($params)
+    protected function requestWillBeSentToPushoverWith($params): void
     {
+        $multipartData = array_map(
+            fn($key, $value) => ['name' => $key, 'contents' => $value],
+            array_keys($params),
+            array_values($params)
+        );
+
         $this->guzzleClient->shouldReceive('post')
             ->with('https://api.pushover.net/1/messages.json', [
-                'form_params' => $params,
+                'multipart' => $multipartData,
             ])
             ->once();
     }
 
-    protected function ignoreEvents()
+    protected function ignoreEvents(): void
     {
         $dispatcher = Mockery::mock('Illuminate\Contracts\Events\Dispatcher');
-        $dispatcher->shouldReceive('fire');
+        $dispatcher->shouldReceive('dispatch');
         app()->instance('events', $dispatcher);
     }
 }
diff --git a/tests/Notifiable.php b/tests/Notifiable.php
index f4e19dc..c5ce36a 100644
--- a/tests/Notifiable.php
+++ b/tests/Notifiable.php
@@ -6,6 +6,11 @@ class Notifiable
 {
     public function routeNotificationFor($channel)
     {
-        return 'pushover-key';
+        return 'pushover-key-30characters-long';
+    }
+
+    public function getKey()
+    {
+        return '1';
     }
 }
diff --git a/tests/NotifiableWithPushoverReceiver.php b/tests/NotifiableWithPushoverReceiver.php
index 072f2e7..d3beff6 100644
--- a/tests/NotifiableWithPushoverReceiver.php
+++ b/tests/NotifiableWithPushoverReceiver.php
@@ -8,7 +8,7 @@ class NotifiableWithPushoverReceiver extends Notifiable
 {
     public function routeNotificationFor($channel)
     {
-        return PushoverReceiver::withUserKey('pushover-key')
+        return PushoverReceiver::withUserKey('pushover-key-30characters-long')
             ->toDevice('iphone')
             ->toDevice('desktop');
     }
diff --git a/tests/NotifiableWithPushoverReceiverWithToken.php b/tests/NotifiableWithPushoverReceiverWithToken.php
index bcff167..f956f35 100644
--- a/tests/NotifiableWithPushoverReceiverWithToken.php
+++ b/tests/NotifiableWithPushoverReceiverWithToken.php
@@ -8,7 +8,7 @@ class NotifiableWithPushoverReceiverWithToken extends Notifiable
 {
     public function routeNotificationFor($channel)
     {
-        return PushoverReceiver::withUserKey('pushover-key')
+        return PushoverReceiver::withUserKey('pushover-key-30characters-long')
             ->withApplicationToken('overridden-application-token')
             ->toDevice('iphone')
             ->toDevice('desktop');
diff --git a/tests/PushoverChannelTest.php b/tests/PushoverChannelTest.php
index 6f7397f..41e8374 100644
--- a/tests/PushoverChannelTest.php
+++ b/tests/PushoverChannelTest.php
@@ -43,56 +43,60 @@ public function setUp(): void
     }
 
     /** @test */
-    public function it_can_send_a_message_to_pushover()
+    public function it_can_send_a_message_to_pushover(): void
     {
         $notifiable = new Notifiable;
 
         $this->notification->shouldReceive('toPushover')
             ->with($notifiable)
             ->andReturn($this->message);
+
         $this->pushover->shouldReceive('send')
             ->with(Mockery::subset([
-                'user' => 'pushover-key',
+                'user' => 'pushover-key-30characters-long',
                 'device' => '',
-            ]))
+            ]), $notifiable)
             ->once();
 
         $this->channel->send($notifiable, $this->notification);
     }
 
     /** @test */
-    public function it_can_send_a_message_to_pushover_using_a_pushover_receiver()
+    public function it_can_send_a_message_to_pushover_using_a_pushover_receiver(): void
     {
         $notifiable = new NotifiableWithPushoverReceiver;
 
         $this->notification->shouldReceive('toPushover')
             ->with($notifiable)
             ->andReturn($this->message);
+
         $this->pushover->shouldReceive('send')
             ->with(Mockery::subset([
-                'user' => 'pushover-key',
+                'user' => 'pushover-key-30characters-long',
                 'device' => 'iphone,desktop',
-            ]))
+            ]), $notifiable)
             ->once();
 
         $this->channel->send($notifiable, $this->notification);
     }
 
     /** @test */
-    public function it_fires_a_notification_failed_event_when_the_communication_with_pushover_failed()
+    public function it_fires_a_notification_failed_event_when_the_communication_with_pushover_failed(): void
     {
         $this->notification->shouldReceive('toPushover')->andReturn($this->message);
         $this->pushover->shouldReceive('send')->andThrow(
             ServiceCommunicationError::communicationFailed(new Exception())
         );
 
-        $this->events->shouldReceive('fire')->with(Mockery::type(NotificationFailed::class));
+        $this->events->shouldReceive('dispatch')->with(Mockery::type(NotificationFailed::class));
 
         $this->channel->send(new Notifiable, $this->notification);
+
+        $this->expectNotToPerformAssertions();
     }
 
     /** @test */
-    public function it_does_not_send_a_message_when_notifiable_does_not_have_route_notificaton_for_pushover()
+    public function it_does_not_send_a_message_when_notifiable_does_not_have_route_notificaton_for_pushover(): void
     {
         $this->notification->shouldReceive('toPushover')->never();
 
diff --git a/tests/PushoverMessageTest.php b/tests/PushoverMessageTest.php
index a2c371e..1440806 100644
--- a/tests/PushoverMessageTest.php
+++ b/tests/PushoverMessageTest.php
@@ -19,7 +19,7 @@ public function setUp(): void
     }
 
     /** @test */
-    public function it_can_accept_a_message_when_constructing_a_message()
+    public function it_can_accept_a_message_when_constructing_a_message(): void
     {
         $message = new PushoverMessage('message text');
 
@@ -27,7 +27,7 @@ public function it_can_accept_a_message_when_constructing_a_message()
     }
 
     /** @test */
-    public function it_can_create_a_message()
+    public function it_can_create_a_message(): void
     {
         $message = PushoverMessage::create();
 
@@ -35,7 +35,7 @@ public function it_can_create_a_message()
     }
 
     /** @test */
-    public function it_can_accept_a_message_when_creating_a_message()
+    public function it_can_accept_a_message_when_creating_a_message(): void
     {
         $message = PushoverMessage::create('message text');
 
@@ -43,7 +43,7 @@ public function it_can_accept_a_message_when_creating_a_message()
     }
 
     /** @test */
-    public function it_can_set_content()
+    public function it_can_set_content(): void
     {
         $this->message->content('message text');
 
@@ -51,7 +51,7 @@ public function it_can_set_content()
     }
 
     /** @test */
-    public function it_can_set_the_message_format_to_plain()
+    public function it_can_set_the_message_format_to_plain(): void
     {
         $this->message->plain();
 
@@ -59,7 +59,7 @@ public function it_can_set_the_message_format_to_plain()
     }
 
     /** @test */
-    public function it_can_set_the_message_format_to_html()
+    public function it_can_set_the_message_format_to_html(): void
     {
         $this->message->html();
 
@@ -67,7 +67,7 @@ public function it_can_set_the_message_format_to_html()
     }
 
     /** @test */
-    public function it_can_set_the_message_format_to_monospace()
+    public function it_can_set_the_message_format_to_monospace(): void
     {
         $this->message->monospace();
 
@@ -75,7 +75,7 @@ public function it_can_set_the_message_format_to_monospace()
     }
 
     /** @test */
-    public function it_can_set_a_title()
+    public function it_can_set_a_title(): void
     {
         $this->message->title('message title');
 
@@ -83,7 +83,7 @@ public function it_can_set_a_title()
     }
 
     /** @test */
-    public function it_can_set_a_time()
+    public function it_can_set_a_time(): void
     {
         $this->message->time(123456789);
 
@@ -91,7 +91,7 @@ public function it_can_set_a_time()
     }
 
     /** @test */
-    public function it_can_set_a_time_from_a_carbon_object()
+    public function it_can_set_a_time_from_a_carbon_object(): void
     {
         $carbon = Carbon::now();
 
@@ -101,7 +101,7 @@ public function it_can_set_a_time_from_a_carbon_object()
     }
 
     /** @test */
-    public function it_can_set_an_url()
+    public function it_can_set_an_url(): void
     {
         $this->message->url('http://example.com');
 
@@ -109,7 +109,7 @@ public function it_can_set_an_url()
     }
 
     /** @test */
-    public function it_can_set_an_url_with_a_title()
+    public function it_can_set_an_url_with_a_title(): void
     {
         $this->message->url('http://example.com', 'Go to example website');
 
@@ -118,7 +118,7 @@ public function it_can_set_an_url_with_a_title()
     }
 
     /** @test */
-    public function it_can_set_a_sound()
+    public function it_can_set_a_sound(): void
     {
         $this->message->sound('boing');
 
@@ -126,7 +126,7 @@ public function it_can_set_a_sound()
     }
 
     /** @test */
-    public function it_can_set_a_priority()
+    public function it_can_set_a_priority(): void
     {
         $this->message->priority(PushoverMessage::NORMAL_PRIORITY);
 
@@ -134,7 +134,7 @@ public function it_can_set_a_priority()
     }
 
     /** @test */
-    public function it_can_set_a_priority_with_retry_and_expire()
+    public function it_can_set_a_priority_with_retry_and_expire(): void
     {
         $this->message->priority(PushoverMessage::EMERGENCY_PRIORITY, 60, 600);
 
@@ -144,7 +144,7 @@ public function it_can_set_a_priority_with_retry_and_expire()
     }
 
     /** @test */
-    public function it_cannot_set_priority_to_emergency_when_not_providing_a_retry_and_expiry_time()
+    public function it_cannot_set_priority_to_emergency_when_not_providing_a_retry_and_expiry_time(): void
     {
         $this->expectException(EmergencyNotificationRequiresRetryAndExpire::class);
 
@@ -152,7 +152,7 @@ public function it_cannot_set_priority_to_emergency_when_not_providing_a_retry_a
     }
 
     /** @test */
-    public function it_can_set_the_priority_to_the_lowest()
+    public function it_can_set_the_priority_to_the_lowest(): void
     {
         $this->message->lowestPriority();
 
@@ -160,7 +160,7 @@ public function it_can_set_the_priority_to_the_lowest()
     }
 
     /** @test */
-    public function it_can_set_the_priority_to_low()
+    public function it_can_set_the_priority_to_low(): void
     {
         $this->message->lowPriority();
 
@@ -168,7 +168,7 @@ public function it_can_set_the_priority_to_low()
     }
 
     /** @test */
-    public function it_can_set_the_priority_to_normal()
+    public function it_can_set_the_priority_to_normal(): void
     {
         $this->message->normalPriority();
 
@@ -176,7 +176,7 @@ public function it_can_set_the_priority_to_normal()
     }
 
     /** @test */
-    public function it_can_set_the_priority_to_high()
+    public function it_can_set_the_priority_to_high(): void
     {
         $this->message->highPriority();
 
@@ -184,7 +184,7 @@ public function it_can_set_the_priority_to_high()
     }
 
     /** @test */
-    public function it_can_set_the_priority_to_emergency()
+    public function it_can_set_the_priority_to_emergency(): void
     {
         $this->message->emergencyPriority(60, 600);
 
diff --git a/tests/PushoverServiceProviderTest.php b/tests/PushoverServiceProviderTest.php
index b692201..000676f 100644
--- a/tests/PushoverServiceProviderTest.php
+++ b/tests/PushoverServiceProviderTest.php
@@ -3,6 +3,7 @@
 namespace NotificationChannels\Pushover\Test;
 
 use Illuminate\Contracts\Foundation\Application;
+use Illuminate\Support\Facades\Config;
 use Mockery;
 use NotificationChannels\Pushover\Pushover;
 use NotificationChannels\Pushover\PushoverChannel;
@@ -28,8 +29,10 @@ public function setUp(): void
     }
 
     /** @test */
-    public function it_gives_an_instantiated_pushover_object_when_the_channel_asks_for_it()
+    public function it_gives_an_instantiated_pushover_object_when_the_channel_asks_for_it(): void
     {
+        Config::shouldReceive('get')->with('services.pushover.token', null)->once()->andReturn('test-token');
+
         $this->app->shouldReceive('when')->with(PushoverChannel::class)->once()->andReturn($this->app);
         $this->app->shouldReceive('needs')->with(Pushover::class)->once()->andReturn($this->app);
         $this->app->shouldReceive('give')->with(Mockery::on(function ($pushover) {
diff --git a/tests/PushoverTest.php b/tests/PushoverTest.php
index d51b8b9..1e546f4 100644
--- a/tests/PushoverTest.php
+++ b/tests/PushoverTest.php
@@ -24,85 +24,91 @@ public function setUp(): void
         parent::setUp();
 
         $this->guzzleClient = Mockery::mock(HttpClient::class);
-        $this->pushover = new Pushover($this->guzzleClient, 'application-token');
+        $this->pushover = new Pushover($this->guzzleClient, 'new-application-token-12345678');
     }
 
     /** @test */
-    public function it_can_send_a_request_to_pushover()
+    public function it_can_send_a_request_to_pushover(): void
     {
         $this->guzzleClient->shouldReceive('post')
             ->with('https://api.pushover.net/1/messages.json', [
-                'form_params' => [
-                    'token' => 'application-token',
+                'multipart' => [
+                    ['name' => 'token', 'contents' => 'new-application-token-12345678'],
                 ],
             ]);
 
-        $this->pushover->send([]);
+        $this->pushover->send([], new Notifiable());
+
+        $this->expectNotToPerformAssertions();
     }
 
     /** @test */
-    public function it_can_send_a_request_with_an_overridden_token()
+    public function it_can_send_a_request_with_an_overridden_token(): void
     {
         $this->guzzleClient->shouldReceive('post')
             ->with('https://api.pushover.net/1/messages.json', [
-                'form_params' => [
-                    'token' => 'dynamic-application-token',
+                'multipart' => [
+                    ['name' => 'token', 'contents' => 'dynamic-application-token-1234'],
                 ],
             ]);
 
-        $this->pushover->send(['token' => 'dynamic-application-token']);
+        $this->pushover->send(['token' => 'dynamic-application-token-1234'], new Notifiable());
+
+        $this->expectNotToPerformAssertions();
     }
 
     /** @test */
-    public function it_can_accept_parameters_for_a_send_request()
+    public function it_can_accept_parameters_for_a_send_request(): void
     {
         $this->guzzleClient->shouldReceive('post')
             ->with('https://api.pushover.net/1/messages.json', [
-                'form_params' => [
-                    'token' => 'application-token',
-                    'content' => 'content of message',
+                'multipart' => [
+                    ['name' => 'token', 'contents' => 'new-application-token-12345678'],
+                    ['name' => 'content', 'contents' => 'content of message'],
                 ],
             ]);
 
         $this->pushover->send([
             'content' => 'content of message',
-        ]);
+        ], new Notifiable());
+
+        $this->expectNotToPerformAssertions();
     }
 
     /** @test */
-    public function it_throws_an_exception_when_pushover_returns_an_error_with_invalid_json()
+    public function it_throws_an_exception_when_pushover_returns_an_error_with_invalid_json(): void
     {
         $this->expectException(CouldNotSendNotification::class);
-        $this->expectExceptionMessage('Pushover responded with an error (400).');
+        $this->expectExceptionMessage('Pushover responded with an error (400)');
 
         $guzzleRequest = Mockery::mock(\Psr\Http\Message\RequestInterface::class);
         $guzzleResponse = Mockery::mock(\Psr\Http\Message\ResponseInterface::class);
         $guzzleResponse->shouldReceive('getStatusCode')->andReturn(400);
-        $guzzleResponse->shouldReceive('getBody')->andReturn('');
+        $guzzleResponse->shouldReceive('getBody->getContents');
 
         $this->guzzleClient->shouldReceive('post')->andThrow(new RequestException('message', $guzzleRequest, $guzzleResponse));
 
-        $this->pushover->send([]);
+        $this->pushover->send([], new Notifiable());
     }
 
     /** @test */
-    public function it_throws_an_exception_when_pushover_returns_an_error_with_valid_json()
+    public function it_throws_an_exception_when_pushover_returns_an_error_with_valid_json(): void
     {
         $this->expectException(CouldNotSendNotification::class);
-        $this->expectExceptionMessage('Pushover responded with an error (400): error_message_1, error_message_2');
+        $this->expectExceptionMessage("Pushover responded with an error (400) for notifiable 'NotificationChannels\Pushover\Test\Notifiable' with id '1': error_message_1, error_message_2");
 
         $guzzleRequest = Mockery::mock(\Psr\Http\Message\RequestInterface::class);
         $guzzleResponse = Mockery::mock(\Psr\Http\Message\ResponseInterface::class);
         $guzzleResponse->shouldReceive('getStatusCode')->andReturn(400);
-        $guzzleResponse->shouldReceive('getBody')->andReturn('{"errors": ["error_message_1", "error_message_2"]}');
+        $guzzleResponse->shouldReceive('getBody->getContents')->andReturn('{"errors": ["error_message_1", "error_message_2"]}');
 
         $this->guzzleClient->shouldReceive('post')->andThrow(new RequestException('message', $guzzleRequest, $guzzleResponse));
 
-        $this->pushover->send([]);
+        $this->pushover->send([], new Notifiable());
     }
 
     /** @test */
-    public function it_throws_an_exception_when_pushover_returns_nothing()
+    public function it_throws_an_exception_when_pushover_returns_nothing(): void
     {
         $this->expectException(ServiceCommunicationError::class);
         $this->expectExceptionMessage('The communication with Pushover failed because');
@@ -111,17 +117,17 @@ public function it_throws_an_exception_when_pushover_returns_nothing()
 
         $this->guzzleClient->shouldReceive('post')->andThrow(new RequestException('message', $guzzleRequest, null));
 
-        $this->pushover->send([]);
+        $this->pushover->send([], new Notifiable());
     }
 
     /** @test */
-    public function it_throws_an_exception_when_an_unknown_communication_error_occurred()
+    public function it_throws_an_exception_when_an_unknown_communication_error_occurred(): void
     {
         $this->expectException(ServiceCommunicationError::class);
         $this->expectExceptionMessage('The communication with Pushover failed');
 
         $this->guzzleClient->shouldReceive('post')->andThrow(new Exception);
 
-        $this->pushover->send([]);
+        $this->pushover->send([], new Notifiable());
     }
 }