diff --git a/composer.json b/composer.json
index 61b217b..770c56c 100644
--- a/composer.json
+++ b/composer.json
@@ -7,7 +7,7 @@
   "license": "MIT",
   "require": {
     "psr/log": ">=1.1",
-    "m2mobi/apns-php": "~3.0",
+    "m2mobi/apns-php": "dev-master",
     "phpmailer/phpmailer": "~6.4",
     "rmccue/requests": "~2.0",
     "php": ">=8.1",
diff --git a/decomposer.json b/decomposer.json
index c60ac73..a6ae248 100644
--- a/decomposer.json
+++ b/decomposer.json
@@ -19,8 +19,8 @@
     },
     "ApnsPHP": {
         "url": "https://github.com/move-backend/apnsphp.git",
-        "version": "3.0.3",
-        "revision": "release/3.0.x",
+        "version": "4.0.0",
+        "revision": "master",
         "psr0": {
             "path": "/"
         }
diff --git a/src/Lunr/Vortex/APNS/APNSPayload.php b/src/Lunr/Vortex/APNS/APNSPayload.php
index e373002..d22b89b 100644
--- a/src/Lunr/Vortex/APNS/APNSPayload.php
+++ b/src/Lunr/Vortex/APNS/APNSPayload.php
@@ -10,7 +10,7 @@
 
 namespace Lunr\Vortex\APNS;
 
-use ReflectionClass;
+use ApnsPHP\Message\Priority;
 
 /**
  * Apple Push Notification Service Payload Generator.
@@ -31,7 +31,7 @@ public function __construct()
     {
         $this->elements = [];
 
-        $this->elements['priority'] = APNSPriority::HIGH;
+        $this->elements['priority'] = Priority::Immediately;
     }
 
     /**
@@ -88,18 +88,13 @@ public function set_topic(string $topic): self
     /**
      * Mark the notification priority.
      *
-     * @param int $priority Notification priority value.
+     * @param Priority $priority Notification priority value.
      *
      * @return APNSPayload Self Reference
      */
-    public function set_priority(int $priority): self
+    public function set_priority(Priority $priority): self
     {
-        $priority_class = new ReflectionClass('\Lunr\Vortex\APNS\APNSPriority');
-
-        if (in_array($priority, array_values($priority_class->getConstants())))
-        {
-            $this->elements['priority'] = $priority;
-        }
+        $this->elements['priority'] = $priority;
 
         return $this;
     }
diff --git a/src/Lunr/Vortex/APNS/APNSPriority.php b/src/Lunr/Vortex/APNS/APNSPriority.php
deleted file mode 100644
index 3f40414..0000000
--- a/src/Lunr/Vortex/APNS/APNSPriority.php
+++ /dev/null
@@ -1,33 +0,0 @@
-<?php
-
-/**
- * This file contains priority types for delivering APNS Notifications.
- *
- * SPDX-FileCopyrightText: Copyright 2021 M2mobi B.V., Amsterdam, The Netherlands
- * SPDX-FileCopyrightText: Copyright 2022 Move Agency Group B.V., Zwolle, The Netherlands
- * SPDX-License-Identifier: MIT
- */
-
-namespace Lunr\Vortex\APNS;
-
-/**
- * APNS Priority Types.
- */
-class APNSPriority
-{
-
-    /**
-     * Deliver notification immediately.
-     * @var int
-     */
-    public const HIGH = 10;
-
-    /**
-     * Deliver notification with normal priority.
-     * @var int
-     */
-    public const NORMAL = 5;
-
-}
-
-?>
diff --git a/src/Lunr/Vortex/APNS/ApnsPHP/Tests/APNSDispatcherPushTest.php b/src/Lunr/Vortex/APNS/ApnsPHP/Tests/APNSDispatcherPushTest.php
index fe46f90..4b6e38b 100644
--- a/src/Lunr/Vortex/APNS/ApnsPHP/Tests/APNSDispatcherPushTest.php
+++ b/src/Lunr/Vortex/APNS/ApnsPHP/Tests/APNSDispatcherPushTest.php
@@ -12,6 +12,7 @@
 
 use ApnsPHP\Exception as ApnsPHPException;
 use ApnsPHP\Message\Exception as MessageException;
+use ApnsPHP\Message\Priority;
 use ApnsPHP\Push\Exception as PushException;
 use Lunr\Vortex\Email\EmailPayload;
 use Lunr\Vortex\FCM\FCMPayload;
@@ -124,7 +125,7 @@ public function testPushConstructsCorrectPayload(): void
             'mutable_content' => TRUE,
             'content_available' => TRUE,
             'topic' => 'com.company.app',
-            'priority' => 5,
+            'priority' => Priority::ConsiderPowerUsage,
             'collapse_key' => 'key',
             'identifier' => 'identifier',
             'yo' => 'he',
diff --git a/src/Lunr/Vortex/APNS/Tests/APNSPayloadSetTest.php b/src/Lunr/Vortex/APNS/Tests/APNSPayloadSetTest.php
index 6916cd5..5663872 100644
--- a/src/Lunr/Vortex/APNS/Tests/APNSPayloadSetTest.php
+++ b/src/Lunr/Vortex/APNS/Tests/APNSPayloadSetTest.php
@@ -10,6 +10,8 @@
 
 namespace Lunr\Vortex\APNS\Tests;
 
+use ApnsPHP\Message\Priority;
+
 /**
  * This class contains tests for the setters of the APNSPayload class.
  *
@@ -311,27 +313,12 @@ public function testSetTopicReturnsSelfReference(): void
      */
     public function testPriority(): void
     {
-        $this->class->set_priority(5);
-
-        $value = $this->get_reflection_property_value('elements');
-
-        $this->assertArrayHasKey('priority', $value);
-        $this->assertEquals(5, $value['priority']);
-    }
-
-    /**
-     * Test set_priority() works correctly.
-     *
-     * @covers \Lunr\Vortex\APNS\APNSPayload::set_priority
-     */
-    public function testPriorityIgnoresWrongValues(): void
-    {
-        $this->class->set_priority(7);
+        $this->class->set_priority(Priority::ConsiderPowerUsage);
 
         $value = $this->get_reflection_property_value('elements');
 
         $this->assertArrayHasKey('priority', $value);
-        $this->assertEquals(10, $value['priority']);
+        $this->assertEquals(Priority::ConsiderPowerUsage, $value['priority']);
     }
 
     /**
@@ -341,7 +328,7 @@ public function testPriorityIgnoresWrongValues(): void
      */
     public function testSetPriorityReturnsSelfReference(): void
     {
-        $this->assertSame($this->class, $this->class->set_priority(5));
+        $this->assertSame($this->class, $this->class->set_priority(Priority::ConsiderPowerUsage));
     }
 
     /**
diff --git a/src/Lunr/Vortex/FCM/FCMApnsPayload.php b/src/Lunr/Vortex/FCM/FCMApnsPayload.php
index 7f12777..490b2fd 100644
--- a/src/Lunr/Vortex/FCM/FCMApnsPayload.php
+++ b/src/Lunr/Vortex/FCM/FCMApnsPayload.php
@@ -9,9 +9,6 @@
 
 namespace Lunr\Vortex\FCM;
 
-use Lunr\Vortex\APNS\APNSPriority;
-use ReflectionClass;
-
 /**
  * Firebase Cloud Messaging Push Notification APNS Payload Generator.
  *
@@ -114,13 +111,11 @@ public function set_mutable_content(bool $mutable): static
      */
     public function set_priority(string $priority): static
     {
-        $priority = strtoupper($priority);
-
-        $priority_class = new ReflectionClass(APNSPriority::class);
-        $priorities     = $priority_class->getConstants();
-        if (in_array($priority, array_keys($priorities)))
+        $priority = strtolower($priority);
+        $matches  = array_filter(FCMApnsPriority::cases(), fn($case) => strtolower($case->name) === $priority);
+        if (count($matches) === 1)
         {
-            $this->elements['headers']['apns-priority'] = $priorities[$priority];
+            $this->elements['headers']['apns-priority'] = (string) array_pop($matches)->value;
         }
 
         return $this;
diff --git a/src/Lunr/Vortex/FCM/FCMApnsPriority.php b/src/Lunr/Vortex/FCM/FCMApnsPriority.php
new file mode 100644
index 0000000..abf4d69
--- /dev/null
+++ b/src/Lunr/Vortex/FCM/FCMApnsPriority.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * This file contains priority types for Firebase Cloud Messaging Notifications to APNS.
+ *
+ * SPDX-FileCopyrightText: Copyright 2024 Move Agency Group B.V., Zwolle, The Netherlands
+ * SPDX-License-Identifier: MIT
+ */
+
+namespace Lunr\Vortex\FCM;
+
+/**
+ * Firebase Cloud Messaging APNS Priority Types.
+ */
+enum FCMApnsPriority: int
+{
+
+    /**
+     * Prioritize the device’s power considerations over all other factors for delivery,
+     * and prevent awakening the device
+     */
+    case Low = 1;
+
+    /**
+     * Send the notification based on power considerations on the user’s device
+     */
+    case Default = 5;
+
+    /**
+     * Send the notification immediately
+     */
+    case High = 10;
+
+}
+
+?>
diff --git a/src/Lunr/Vortex/FCM/Tests/FCMApnsPayloadSetTest.php b/src/Lunr/Vortex/FCM/Tests/FCMApnsPayloadSetTest.php
index 1ddcb34..f622e39 100644
--- a/src/Lunr/Vortex/FCM/Tests/FCMApnsPayloadSetTest.php
+++ b/src/Lunr/Vortex/FCM/Tests/FCMApnsPayloadSetTest.php
@@ -98,20 +98,43 @@ public function testSetMutableContentReturnsSelfReference(): void
         $this->assertSame($this->class, $this->class->set_mutable_content(TRUE));
     }
 
+    /**
+     * Provide different priority options for testing.
+     *
+     * @return array
+     */
+    public function priorityProvider(): array
+    {
+        $return = [];
+
+        $return['lowercase'] = [ 'high', 10 ];
+        $return['titlecase'] = [ 'High', 10 ];
+        $return['uppercase'] = [ 'HIGH', 10 ];
+        $return['default']   = [ 'default', 5 ];
+        $return['low']       = [ 'low', 1 ];
+
+        return $return;
+    }
+
     /**
      * Test set_priority() works correctly.
      *
+     * @dataProvider priorityProvider
+     *
+     * @param string $priority The priority to set
+     * @param int    $expected The expected value
+     *
      * @covers \Lunr\Vortex\FCM\FCMApnsPayload::set_priority
      */
-    public function testSetPriority(): void
+    public function testSetPriority(string $priority, int $expected): void
     {
-        $this->class->set_priority('high');
+        $this->class->set_priority($priority);
 
         $value = $this->get_reflection_property_value('elements');
 
         $this->assertArrayHasKey('headers', $value);
         $this->assertArrayHasKey('apns-priority', $value['headers']);
-        $this->assertEquals(10, $value['headers']['apns-priority']);
+        $this->assertEquals($expected, $value['headers']['apns-priority']);
     }
 
     /**