diff --git a/files/lib/system/message/type/AttachmentMessageType.class.php b/files/lib/system/message/type/AttachmentMessageType.class.php
index dc4ba12..0212493 100644
--- a/files/lib/system/message/type/AttachmentMessageType.class.php
+++ b/files/lib/system/message/type/AttachmentMessageType.class.php
@@ -42,7 +42,7 @@ public function __construct()
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Plain';
     }
@@ -50,13 +50,13 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canDelete(Message $message, ?UserProfile $user = null)
+    public function canDelete(Message $message, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
         }
 
-        return $user->getPermission('mod.chat.canDelete');
+        return !!$user->getPermission('mod.chat.canDelete');
     }
 
     /**
diff --git a/files/lib/system/message/type/AwayMessageType.class.php b/files/lib/system/message/type/AwayMessageType.class.php
index c69818b..3718df5 100644
--- a/files/lib/system/message/type/AwayMessageType.class.php
+++ b/files/lib/system/message/type/AwayMessageType.class.php
@@ -31,7 +31,7 @@ final class AwayMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Away';
     }
@@ -39,7 +39,7 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -63,7 +63,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -87,7 +87,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/BackMessageType.class.php b/files/lib/system/message/type/BackMessageType.class.php
index 47dfd90..f9bf3ef 100644
--- a/files/lib/system/message/type/BackMessageType.class.php
+++ b/files/lib/system/message/type/BackMessageType.class.php
@@ -31,7 +31,7 @@ final class BackMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Back';
     }
@@ -39,7 +39,7 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -63,7 +63,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -87,7 +87,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/BroadcastMessageType.class.php b/files/lib/system/message/type/BroadcastMessageType.class.php
index e425c68..bbd74a9 100644
--- a/files/lib/system/message/type/BroadcastMessageType.class.php
+++ b/files/lib/system/message/type/BroadcastMessageType.class.php
@@ -39,7 +39,7 @@ public function __construct()
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Broadcast';
     }
@@ -55,7 +55,7 @@ public function getPayload(Message $message, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -75,7 +75,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -95,19 +95,19 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function canDelete(Message $message, ?UserProfile $user = null)
+    public function canDelete(Message $message, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
         }
 
-        return $user->getPermission('mod.chat.canDelete');
+        return !!$user->getPermission('mod.chat.canDelete');
     }
 
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/ChatUpdateMessageType.class.php b/files/lib/system/message/type/ChatUpdateMessageType.class.php
index 7ed0589..7d79283 100644
--- a/files/lib/system/message/type/ChatUpdateMessageType.class.php
+++ b/files/lib/system/message/type/ChatUpdateMessageType.class.php
@@ -29,7 +29,7 @@ final class ChatUpdateMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/ChatUpdate';
     }
@@ -37,7 +37,7 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         return true;
     }
@@ -45,7 +45,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         return true;
     }
@@ -53,7 +53,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/ColorMessageType.class.php b/files/lib/system/message/type/ColorMessageType.class.php
index 026ea7f..9459c09 100644
--- a/files/lib/system/message/type/ColorMessageType.class.php
+++ b/files/lib/system/message/type/ColorMessageType.class.php
@@ -31,7 +31,7 @@ final class ColorMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Color';
     }
@@ -39,7 +39,7 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -59,7 +59,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         return false;
     }
@@ -67,7 +67,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/InfoMessageType.class.php b/files/lib/system/message/type/InfoMessageType.class.php
index 12eb9f7..dd49dbc 100644
--- a/files/lib/system/message/type/InfoMessageType.class.php
+++ b/files/lib/system/message/type/InfoMessageType.class.php
@@ -26,7 +26,7 @@ final class InfoMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Info';
     }
diff --git a/files/lib/system/message/type/JoinMessageType.class.php b/files/lib/system/message/type/JoinMessageType.class.php
index d66f4df..705a151 100644
--- a/files/lib/system/message/type/JoinMessageType.class.php
+++ b/files/lib/system/message/type/JoinMessageType.class.php
@@ -26,7 +26,7 @@ final class JoinMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Join';
     }
diff --git a/files/lib/system/message/type/LeaveMessageType.class.php b/files/lib/system/message/type/LeaveMessageType.class.php
index 63670dd..43781e2 100644
--- a/files/lib/system/message/type/LeaveMessageType.class.php
+++ b/files/lib/system/message/type/LeaveMessageType.class.php
@@ -26,7 +26,7 @@ final class LeaveMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Leave';
     }
diff --git a/files/lib/system/message/type/MeMessageType.class.php b/files/lib/system/message/type/MeMessageType.class.php
index fd9fd3a..0562a09 100644
--- a/files/lib/system/message/type/MeMessageType.class.php
+++ b/files/lib/system/message/type/MeMessageType.class.php
@@ -30,7 +30,7 @@ final class MeMessageType implements IMessageType, IDeletableMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Me';
     }
@@ -38,12 +38,12 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canDelete(Message $message, ?UserProfile $user = null)
+    public function canDelete(Message $message, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
         }
 
-        return $user->getPermission('mod.chat.canDelete');
+        return !!$user->getPermission('mod.chat.canDelete');
     }
 }
diff --git a/files/lib/system/message/type/PlainMessageType.class.php b/files/lib/system/message/type/PlainMessageType.class.php
index 5128d53..897ebd1 100644
--- a/files/lib/system/message/type/PlainMessageType.class.php
+++ b/files/lib/system/message/type/PlainMessageType.class.php
@@ -42,7 +42,7 @@ public function __construct()
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Plain';
     }
@@ -50,13 +50,13 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canDelete(Message $message, ?UserProfile $user = null)
+    public function canDelete(Message $message, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
         }
 
-        return $user->getPermission('mod.chat.canDelete');
+        return !!$user->getPermission('mod.chat.canDelete');
     }
 
     /**
diff --git a/files/lib/system/message/type/SuspendMessageType.class.php b/files/lib/system/message/type/SuspendMessageType.class.php
index 1d9e08e..e3f657a 100644
--- a/files/lib/system/message/type/SuspendMessageType.class.php
+++ b/files/lib/system/message/type/SuspendMessageType.class.php
@@ -29,7 +29,7 @@ final class SuspendMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Suspend';
     }
@@ -59,7 +59,7 @@ public function getPayload(Message $message, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -79,7 +79,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -99,7 +99,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/TCanSeeCreator.class.php b/files/lib/system/message/type/TCanSeeCreator.class.php
index 81e423a..442b528 100644
--- a/files/lib/system/message/type/TCanSeeCreator.class.php
+++ b/files/lib/system/message/type/TCanSeeCreator.class.php
@@ -30,7 +30,7 @@ trait TCanSeeCreator
     /**
      * @see \chat\system\message\type\IMessageType::canSee()
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -50,7 +50,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @see \chat\system\message\type\IMessageType::canSeeInLog()
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -70,7 +70,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @see \chat\system\message\type\IMessageType::supportsFastSelect()
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         $parameters = [
             'result' => true,
diff --git a/files/lib/system/message/type/TCanSeeInSameRoom.class.php b/files/lib/system/message/type/TCanSeeInSameRoom.class.php
index 6f3172e..a74ab40 100644
--- a/files/lib/system/message/type/TCanSeeInSameRoom.class.php
+++ b/files/lib/system/message/type/TCanSeeInSameRoom.class.php
@@ -29,7 +29,7 @@ trait TCanSeeInSameRoom
     /**
      * @see \chat\system\message\type\IMessageType::canSee()
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -49,7 +49,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @see \chat\system\message\type\IMessageType::canSeeInLog()
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -69,7 +69,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @see \chat\system\message\type\IMessageType::supportsFastSelect()
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         $parameters = [
             'result' => true,
diff --git a/files/lib/system/message/type/TeamMessageType.class.php b/files/lib/system/message/type/TeamMessageType.class.php
index fe8045b..9005956 100644
--- a/files/lib/system/message/type/TeamMessageType.class.php
+++ b/files/lib/system/message/type/TeamMessageType.class.php
@@ -39,7 +39,7 @@ public function __construct()
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Team';
     }
@@ -55,19 +55,19 @@ public function getPayload(Message $message, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canDelete(Message $message, ?UserProfile $user = null)
+    public function canDelete(Message $message, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
         }
 
-        return $user->getPermission('mod.chat.canDelete');
+        return !!$user->getPermission('mod.chat.canDelete');
     }
 
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -77,7 +77,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
             'message' => $message,
             'room' => $room,
             'user' => $user,
-            'canSee' => $user->getPermission('mod.chat.canTeam'),
+            'canSee' => !!$user->getPermission('mod.chat.canTeam'),
         ];
         EventHandler::getInstance()->fireAction($this, 'canSee', $parameters);
 
@@ -87,7 +87,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -97,7 +97,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
             'message' => $message,
             'room' => $room,
             'user' => $user,
-            'canSee' => $user->getPermission('mod.chat.canTeam'),
+            'canSee' => !!$user->getPermission('mod.chat.canTeam'),
         ];
         EventHandler::getInstance()->fireAction($this, 'canSeeInLog', $parameters);
 
@@ -107,7 +107,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/TemproomCreatedMessageType.class.php b/files/lib/system/message/type/TemproomCreatedMessageType.class.php
index 08f9935..a441873 100644
--- a/files/lib/system/message/type/TemproomCreatedMessageType.class.php
+++ b/files/lib/system/message/type/TemproomCreatedMessageType.class.php
@@ -26,7 +26,7 @@ final class TemproomCreatedMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/TemproomCreated';
     }
diff --git a/files/lib/system/message/type/TemproomInvitedMessageType.class.php b/files/lib/system/message/type/TemproomInvitedMessageType.class.php
index 2e0298c..771eb76 100644
--- a/files/lib/system/message/type/TemproomInvitedMessageType.class.php
+++ b/files/lib/system/message/type/TemproomInvitedMessageType.class.php
@@ -29,7 +29,7 @@ final class TemproomInvitedMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/TemproomInvited';
     }
@@ -64,7 +64,7 @@ public function getPayload(Message $message, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -84,7 +84,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -104,7 +104,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         $parameters = [
             'result' => false,
diff --git a/files/lib/system/message/type/TombstoneMessageType.class.php b/files/lib/system/message/type/TombstoneMessageType.class.php
index 6aa2fe0..6ffd71e 100644
--- a/files/lib/system/message/type/TombstoneMessageType.class.php
+++ b/files/lib/system/message/type/TombstoneMessageType.class.php
@@ -31,7 +31,7 @@ final class TombstoneMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Tombstone';
     }
@@ -39,7 +39,7 @@ public function getJavaScriptModuleName()
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -59,7 +59,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         return false;
     }
@@ -67,7 +67,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/UnsuspendMessageType.class.php b/files/lib/system/message/type/UnsuspendMessageType.class.php
index 966cb8d..f97ab95 100644
--- a/files/lib/system/message/type/UnsuspendMessageType.class.php
+++ b/files/lib/system/message/type/UnsuspendMessageType.class.php
@@ -29,7 +29,7 @@ final class UnsuspendMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Unsuspend';
     }
@@ -59,7 +59,7 @@ public function getPayload(Message $message, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -79,7 +79,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -99,7 +99,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         return false;
     }
diff --git a/files/lib/system/message/type/WhereMessageType.class.php b/files/lib/system/message/type/WhereMessageType.class.php
index b7e2cbf..0db80e0 100644
--- a/files/lib/system/message/type/WhereMessageType.class.php
+++ b/files/lib/system/message/type/WhereMessageType.class.php
@@ -31,7 +31,7 @@ final class WhereMessageType implements IMessageType
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Where';
     }
diff --git a/files/lib/system/message/type/WhisperMessageType.class.php b/files/lib/system/message/type/WhisperMessageType.class.php
index a931a0e..b4ef97c 100644
--- a/files/lib/system/message/type/WhisperMessageType.class.php
+++ b/files/lib/system/message/type/WhisperMessageType.class.php
@@ -41,7 +41,7 @@ public function __construct()
     /**
      * @inheritDoc
      */
-    public function getJavaScriptModuleName()
+    public function getJavaScriptModuleName(): string
     {
         return 'Bastelstu.be/Chat/MessageType/Whisper';
     }
@@ -91,7 +91,7 @@ public function getPayload(Message $message, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSee(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSee(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -111,7 +111,7 @@ public function canSee(Message $message, Room $room, ?UserProfile $user = null)
     /**
      * @inheritDoc
      */
-    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null)
+    public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = null): bool
     {
         if ($user === null) {
             $user = new UserProfile(WCF::getUser());
@@ -131,7 +131,7 @@ public function canSeeInLog(Message $message, Room $room, ?UserProfile $user = n
     /**
      * @inheritDoc
      */
-    public function supportsFastSelect()
+    public function supportsFastSelect(): bool
     {
         $parameters = [
             'result' => false,