diff --git a/extensions/akismet/extend.php b/extensions/akismet/extend.php
index 0e9a96d37..d233931b4 100644
--- a/extensions/akismet/extend.php
+++ b/extensions/akismet/extend.php
@@ -13,6 +13,7 @@ use Flarum\Approval\Event\PostWasApproved;
 use Flarum\Extend;
 use Flarum\Post\Event\Hidden;
 use Flarum\Post\Event\Saving;
+use Flarum\Post\Post;
 
 return [
     (new Extend\Frontend('forum'))
@@ -30,4 +31,7 @@ return [
 
     (new Extend\ServiceProvider())
         ->register(AkismetProvider::class),
+
+    (new Extend\Model(Post::class))
+        ->cast('is_spam', 'bool'),
 ];
diff --git a/extensions/akismet/src/Listener/ValidatePost.php b/extensions/akismet/src/Listener/ValidatePost.php
index ef5aa5ff3..d0855b1cc 100644
--- a/extensions/akismet/src/Listener/ValidatePost.php
+++ b/extensions/akismet/src/Listener/ValidatePost.php
@@ -50,7 +50,7 @@ class ValidatePost
             ->withContent($post->content)
             ->withAuthorName($post->user->username)
             ->withAuthorEmail($post->user->email)
-            ->withType($post->number == 1 ? 'forum-post' : 'reply')
+            ->withType($post->number === 1 ? 'forum-post' : 'reply')
             ->withIp($post->ip_address)
             ->withUserAgent($_SERVER['HTTP_USER_AGENT'])
             ->checkSpam();
diff --git a/extensions/approval/extend.php b/extensions/approval/extend.php
index edc5b61d3..c18e612a8 100644
--- a/extensions/approval/extend.php
+++ b/extensions/approval/extend.php
@@ -28,15 +28,17 @@ return [
 
     // Discussions should be approved by default
     (new Extend\Model(Discussion::class))
-        ->default('is_approved', true),
+        ->default('is_approved', true)
+        ->cast('is_approved', 'bool'),
 
     // Posts should be approved by default
     (new Extend\Model(Post::class))
-        ->default('is_approved', true),
+        ->default('is_approved', true)
+        ->cast('is_approved', 'bool'),
 
     (new Extend\ApiSerializer(BasicDiscussionSerializer::class))
         ->attribute('isApproved', function ($serializer, Discussion $discussion) {
-            return (bool) $discussion->is_approved;
+            return $discussion->is_approved;
         }),
 
     (new Extend\ApiSerializer(PostSerializer::class))
diff --git a/extensions/approval/src/Listener/UnapproveNewContent.php b/extensions/approval/src/Listener/UnapproveNewContent.php
index e35d62a0b..d53965ba9 100644
--- a/extensions/approval/src/Listener/UnapproveNewContent.php
+++ b/extensions/approval/src/Listener/UnapproveNewContent.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Approval\Listener;
 
+use Carbon\Carbon;
 use Flarum\Discussion\Discussion;
 use Flarum\Flags\Flag;
 use Flarum\Post\CommentPost;
@@ -55,7 +56,7 @@ class UnapproveNewContent
 
                 $flag->post_id = $post->id;
                 $flag->type = 'approval';
-                $flag->created_at = time();
+                $flag->created_at = Carbon::now();
 
                 $flag->save();
             });
diff --git a/extensions/approval/src/Listener/UpdateDiscussionAfterPostApproval.php b/extensions/approval/src/Listener/UpdateDiscussionAfterPostApproval.php
index 2a62b533c..bcba77b19 100644
--- a/extensions/approval/src/Listener/UpdateDiscussionAfterPostApproval.php
+++ b/extensions/approval/src/Listener/UpdateDiscussionAfterPostApproval.php
@@ -22,7 +22,7 @@ class UpdateDiscussionAfterPostApproval
         $discussion->refreshCommentCount();
         $discussion->refreshLastPost();
 
-        if ($post->number == 1) {
+        if ($post->number === 1) {
             $discussion->is_approved = true;
 
             $discussion->afterSave(function () use ($user) {
diff --git a/extensions/flags/extend.php b/extensions/flags/extend.php
index 3bb468454..3bc6db108 100644
--- a/extensions/flags/extend.php
+++ b/extensions/flags/extend.php
@@ -46,7 +46,7 @@ return [
         ->delete('/posts/{id}/flags', 'flags.delete', DeleteFlagsController::class),
 
     (new Extend\Model(User::class))
-        ->dateAttribute('read_flags_at'),
+        ->cast('read_flags_at', 'datetime'),
 
     (new Extend\Model(Post::class))
         ->hasMany('flags', Flag::class, 'post_id'),
diff --git a/extensions/flags/src/Api/Controller/ListFlagsController.php b/extensions/flags/src/Api/Controller/ListFlagsController.php
index 2b0af8491..edbeac38f 100644
--- a/extensions/flags/src/Api/Controller/ListFlagsController.php
+++ b/extensions/flags/src/Api/Controller/ListFlagsController.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Flags\Api\Controller;
 
+use Carbon\Carbon;
 use Flarum\Api\Controller\AbstractListController;
 use Flarum\Flags\Api\Serializer\FlagSerializer;
 use Flarum\Flags\Flag;
@@ -43,7 +44,7 @@ class ListFlagsController extends AbstractListController
 
         $actor->assertRegistered();
 
-        $actor->read_flags_at = time();
+        $actor->read_flags_at = Carbon::now();
         $actor->save();
 
         $flags = Flag::whereVisibleTo($actor)
diff --git a/extensions/flags/src/Api/Serializer/FlagSerializer.php b/extensions/flags/src/Api/Serializer/FlagSerializer.php
index 91ce26c1c..f307e3d7a 100644
--- a/extensions/flags/src/Api/Serializer/FlagSerializer.php
+++ b/extensions/flags/src/Api/Serializer/FlagSerializer.php
@@ -12,6 +12,8 @@ namespace Flarum\Flags\Api\Serializer;
 use Flarum\Api\Serializer\AbstractSerializer;
 use Flarum\Api\Serializer\BasicUserSerializer;
 use Flarum\Api\Serializer\PostSerializer;
+use Flarum\Flags\Flag;
+use InvalidArgumentException;
 
 class FlagSerializer extends AbstractSerializer
 {
@@ -20,11 +22,14 @@ class FlagSerializer extends AbstractSerializer
      */
     protected $type = 'flags';
 
-    /**
-     * {@inheritdoc}
-     */
     protected function getDefaultAttributes($flag)
     {
+        if (! ($flag instanceof Flag)) {
+            throw new InvalidArgumentException(
+                get_class($this).' can only serialize instances of '.Flag::class
+            );
+        }
+
         return [
             'type'         => $flag->type,
             'reason'       => $flag->reason,
diff --git a/extensions/flags/src/Command/CreateFlagHandler.php b/extensions/flags/src/Command/CreateFlagHandler.php
index abea0a7d6..1798ef95d 100644
--- a/extensions/flags/src/Command/CreateFlagHandler.php
+++ b/extensions/flags/src/Command/CreateFlagHandler.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Flags\Command;
 
+use Carbon\Carbon;
 use Flarum\Flags\Event\Created;
 use Flarum\Flags\Flag;
 use Flarum\Foundation\ValidationException;
@@ -99,7 +100,7 @@ class CreateFlagHandler
         $flag->type = 'user';
         $flag->reason = Arr::get($data, 'attributes.reason');
         $flag->reason_detail = Arr::get($data, 'attributes.reasonDetail');
-        $flag->created_at = time();
+        $flag->created_at = Carbon::now();
 
         $flag->save();
 
diff --git a/extensions/flags/src/Command/DeleteFlagsHandler.php b/extensions/flags/src/Command/DeleteFlagsHandler.php
index 1061a5e50..18173b8ad 100644
--- a/extensions/flags/src/Command/DeleteFlagsHandler.php
+++ b/extensions/flags/src/Command/DeleteFlagsHandler.php
@@ -11,7 +11,7 @@ namespace Flarum\Flags\Command;
 
 use Flarum\Flags\Event\Deleting;
 use Flarum\Flags\Event\FlagsWillBeDeleted;
-use Flarum\Flags\Flag;
+use Flarum\Post\Post;
 use Flarum\Post\PostRepository;
 use Illuminate\Events\Dispatcher;
 
@@ -39,7 +39,7 @@ class DeleteFlagsHandler
 
     /**
      * @param DeleteFlags $command
-     * @return Flag
+     * @return Post
      */
     public function handle(DeleteFlags $command)
     {
diff --git a/extensions/flags/src/Flag.php b/extensions/flags/src/Flag.php
index ee91f8035..6f056469d 100644
--- a/extensions/flags/src/Flag.php
+++ b/extensions/flags/src/Flag.php
@@ -9,11 +9,23 @@
 
 namespace Flarum\Flags;
 
+use Carbon\Carbon;
 use Flarum\Database\AbstractModel;
 use Flarum\Database\ScopeVisibilityTrait;
 use Flarum\Post\Post;
 use Flarum\User\User;
 
+/**
+ * @property int $post_id
+ * @property int $user_id
+ * @property string $type
+ * @property string $reason
+ * @property string $reason_detail
+ * @property Carbon $created_at
+ *
+ * @property-read Post $post
+ * @property-read User $user
+ */
 class Flag extends AbstractModel
 {
     use ScopeVisibilityTrait;
diff --git a/extensions/lock/extend.php b/extensions/lock/extend.php
index 100be10f6..9cf4429c6 100644
--- a/extensions/lock/extend.php
+++ b/extensions/lock/extend.php
@@ -35,12 +35,15 @@ return [
     (new Extend\Notification())
         ->type(DiscussionLockedBlueprint::class, BasicDiscussionSerializer::class, ['alert']),
 
+    (new Extend\Model(Discussion::class))
+        ->cast('is_locked', 'bool'),
+
     (new Extend\ApiSerializer(DiscussionSerializer::class))
         ->attribute('isLocked', function (DiscussionSerializer $serializer, Discussion $discussion) {
-            return (bool) $discussion->is_locked;
+            return $discussion->is_locked;
         })
         ->attribute('canLock', function (DiscussionSerializer $serializer, Discussion $discussion) {
-            return (bool) $serializer->getActor()->can('lock', $discussion);
+            return $serializer->getActor()->can('lock', $discussion);
         }),
 
     (new Extend\Post())
diff --git a/extensions/lock/src/Access/DiscussionPolicy.php b/extensions/lock/src/Access/DiscussionPolicy.php
index 643136a15..86a0e3571 100755
--- a/extensions/lock/src/Access/DiscussionPolicy.php
+++ b/extensions/lock/src/Access/DiscussionPolicy.php
@@ -18,7 +18,7 @@ class DiscussionPolicy extends AbstractPolicy
     /**
      * @param User $actor
      * @param Discussion $discussion
-     * @return bool
+     * @return string|void
      */
     public function reply(User $actor, Discussion $discussion)
     {
diff --git a/extensions/lock/src/Post/DiscussionLockedPost.php b/extensions/lock/src/Post/DiscussionLockedPost.php
index a13c7f7e2..a379fe642 100755
--- a/extensions/lock/src/Post/DiscussionLockedPost.php
+++ b/extensions/lock/src/Post/DiscussionLockedPost.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Lock\Post;
 
+use Carbon\Carbon;
 use Flarum\Post\AbstractEventPost;
 use Flarum\Post\MergeableInterface;
 use Flarum\Post\Post;
@@ -59,7 +60,7 @@ class DiscussionLockedPost extends AbstractEventPost implements MergeableInterfa
         $post = new static;
 
         $post->content = static::buildContent($isLocked);
-        $post->created_at = time();
+        $post->created_at = Carbon::now();
         $post->discussion_id = $discussionId;
         $post->user_id = $userId;
 
diff --git a/extensions/mentions/src/ConfigureMentions.php b/extensions/mentions/src/ConfigureMentions.php
index 8378e3285..296291c20 100644
--- a/extensions/mentions/src/ConfigureMentions.php
+++ b/extensions/mentions/src/ConfigureMentions.php
@@ -16,6 +16,7 @@ use Flarum\Settings\SettingsRepositoryInterface;
 use Flarum\User\User;
 use Illuminate\Support\Str;
 use s9e\TextFormatter\Configurator;
+use s9e\TextFormatter\Parser\Tag;
 
 class ConfigureMentions
 {
@@ -39,7 +40,7 @@ class ConfigureMentions
         $this->configureGroupMentions($config);
     }
 
-    private function configureUserMentions(Configurator $config)
+    private function configureUserMentions(Configurator $config): void
     {
         $config->rendering->parameters['PROFILE_URL'] = $this->url->to('forum')->route('user', ['username' => '']);
 
@@ -66,9 +67,8 @@ class ConfigureMentions
     }
 
     /**
-     * @param $tag
-     *
-     * @return bool
+     * @param Tag $tag
+     * @return bool|void
      */
     public static function addUserId($tag)
     {
@@ -81,7 +81,7 @@ class ConfigureMentions
         }
 
         if (isset($user)) {
-            $tag->setAttribute('id', $user->id);
+            $tag->setAttribute('id', (string) $user->id);
             $tag->setAttribute('displayname', $user->display_name);
 
             return true;
@@ -90,7 +90,7 @@ class ConfigureMentions
         $tag->invalidate();
     }
 
-    private function configurePostMentions(Configurator $config)
+    private function configurePostMentions(Configurator $config): void
     {
         $config->rendering->parameters['DISCUSSION_URL'] = $this->url->to('forum')->route('discussion', ['id' => '']);
 
@@ -122,8 +122,8 @@ class ConfigureMentions
     }
 
     /**
-     * @param $tag
-     * @return bool
+     * @param Tag $tag
+     * @return bool|void
      */
     public static function addPostId($tag, User $actor)
     {
@@ -132,8 +132,8 @@ class ConfigureMentions
             ->find($tag->getAttribute('id'));
 
         if ($post) {
-            $tag->setAttribute('discussionid', (int) $post->discussion_id);
-            $tag->setAttribute('number', (int) $post->number);
+            $tag->setAttribute('discussionid', (string) $post->discussion_id);
+            $tag->setAttribute('number', (string) $post->number);
 
             if ($post->user) {
                 $tag->setAttribute('displayname', $post->user->display_name);
@@ -171,7 +171,7 @@ class ConfigureMentions
 
     /**
      * @param $tag
-     * @return bool
+     * @return bool|void
      */
     public static function addGroupId($tag)
     {
@@ -208,7 +208,7 @@ class ConfigureMentions
 
         $hexNumbers = Str::replace('#', '', $hexColor);
         if (Str::length($hexNumbers) === 3) {
-            $hexNumbers += $hexNumbers;
+            $hexNumbers .= $hexNumbers;
         }
 
         $r = hexdec(Str::substr($hexNumbers, 0, 2));
diff --git a/extensions/mentions/src/Formatter/FormatPostMentions.php b/extensions/mentions/src/Formatter/FormatPostMentions.php
index 289376a7e..45a485e57 100644
--- a/extensions/mentions/src/Formatter/FormatPostMentions.php
+++ b/extensions/mentions/src/Formatter/FormatPostMentions.php
@@ -29,11 +29,11 @@ class FormatPostMentions
     /**
      * Configure rendering for post mentions.
      *
-     * @param s9e\TextFormatter\Renderer $renderer
+     * @param \s9e\TextFormatter\Renderer $renderer
      * @param mixed $context
      * @param string|null $xml
-     * @param Psr\Http\Message\ServerRequestInterface $request
-     * @return void
+     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @return string
      */
     public function __invoke(Renderer $renderer, $context, $xml, Request $request = null)
     {
diff --git a/extensions/mentions/src/Formatter/FormatUserMentions.php b/extensions/mentions/src/Formatter/FormatUserMentions.php
index f0e6fdbb6..5625ac957 100644
--- a/extensions/mentions/src/Formatter/FormatUserMentions.php
+++ b/extensions/mentions/src/Formatter/FormatUserMentions.php
@@ -37,9 +37,9 @@ class FormatUserMentions
     /**
      * Configure rendering for user mentions.
      *
-     * @param s9e\TextFormatter\Renderer $renderer
+     * @param \s9e\TextFormatter\Renderer $renderer
      * @param mixed $context
-     * @param string|null $xml
+     * @param string $xml
      * @return string $xml to be rendered
      */
     public function __invoke(Renderer $renderer, $context, string $xml)
diff --git a/extensions/mentions/src/Listener/UpdateMentionsMetadataWhenVisible.php b/extensions/mentions/src/Listener/UpdateMentionsMetadataWhenVisible.php
index 231f6cfd7..366445984 100755
--- a/extensions/mentions/src/Listener/UpdateMentionsMetadataWhenVisible.php
+++ b/extensions/mentions/src/Listener/UpdateMentionsMetadataWhenVisible.php
@@ -40,7 +40,7 @@ class UpdateMentionsMetadataWhenVisible
      */
     public function handle($event)
     {
-        $content = $event->post->parsedContent;
+        $content = $event->post->parsed_content;
 
         $this->syncUserMentions(
             $event->post,
diff --git a/extensions/nicknames/extend.php b/extensions/nicknames/extend.php
index 535b5cc12..99fb7ab7b 100644
--- a/extensions/nicknames/extend.php
+++ b/extensions/nicknames/extend.php
@@ -26,6 +26,9 @@ return [
 
     new Extend\Locales(__DIR__.'/locale'),
 
+    (new Extend\Model(User::class))
+        ->cast('nickname', 'string'),
+
     (new Extend\User())
         ->displayNameDriver('nickname', NicknameDriver::class),
 
diff --git a/extensions/nicknames/src/NicknameFullTextGambit.php b/extensions/nicknames/src/NicknameFullTextGambit.php
index e80e9f0dd..84cec8035 100644
--- a/extensions/nicknames/src/NicknameFullTextGambit.php
+++ b/extensions/nicknames/src/NicknameFullTextGambit.php
@@ -58,5 +58,7 @@ class NicknameFullTextGambit implements GambitInterface
                 'id',
                 $this->getUserSearchSubQuery($searchValue)
             );
+
+        return true;
     }
 }
diff --git a/extensions/package-manager/src/Api/Controller/ListTasksController.php b/extensions/package-manager/src/Api/Controller/ListTasksController.php
index 666e179f9..115888500 100644
--- a/extensions/package-manager/src/Api/Controller/ListTasksController.php
+++ b/extensions/package-manager/src/Api/Controller/ListTasksController.php
@@ -58,7 +58,7 @@ class ListTasksController extends AbstractListController
 
         $total = $this->repository->query()->count();
 
-        $document->addMeta('total', $total);
+        $document->addMeta('total', (string) $total);
 
         $document->addPaginationLinks(
             $this->url->to('api')->route('package-manager.tasks.index'),
diff --git a/extensions/package-manager/src/Command/BusinessCommandInterface.php b/extensions/package-manager/src/Command/AbstractActionCommand.php
similarity index 53%
rename from extensions/package-manager/src/Command/BusinessCommandInterface.php
rename to extensions/package-manager/src/Command/AbstractActionCommand.php
index 6b13f3b39..45ce09320 100644
--- a/extensions/package-manager/src/Command/BusinessCommandInterface.php
+++ b/extensions/package-manager/src/Command/AbstractActionCommand.php
@@ -9,7 +9,14 @@
 
 namespace Flarum\PackageManager\Command;
 
-interface BusinessCommandInterface
+use Flarum\PackageManager\Task\Task;
+
+abstract class AbstractActionCommand
 {
-    public function getOperationName(): string;
+    /**
+     * @var Task|null
+     */
+    public $task = null;
+
+    abstract public function getOperationName(): string;
 }
diff --git a/extensions/package-manager/src/Command/CheckForUpdates.php b/extensions/package-manager/src/Command/CheckForUpdates.php
index 62280c23f..2ca6efcb4 100755
--- a/extensions/package-manager/src/Command/CheckForUpdates.php
+++ b/extensions/package-manager/src/Command/CheckForUpdates.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class CheckForUpdates implements BusinessCommandInterface
+class CheckForUpdates extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var \Flarum\User\User
      */
diff --git a/extensions/package-manager/src/Command/GlobalUpdate.php b/extensions/package-manager/src/Command/GlobalUpdate.php
index 5dfa5219b..a2fb69f34 100644
--- a/extensions/package-manager/src/Command/GlobalUpdate.php
+++ b/extensions/package-manager/src/Command/GlobalUpdate.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class GlobalUpdate implements BusinessCommandInterface
+class GlobalUpdate extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var \Flarum\User\User
      */
diff --git a/extensions/package-manager/src/Command/MajorUpdate.php b/extensions/package-manager/src/Command/MajorUpdate.php
index d2c3d3462..97bae589b 100644
--- a/extensions/package-manager/src/Command/MajorUpdate.php
+++ b/extensions/package-manager/src/Command/MajorUpdate.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class MajorUpdate implements BusinessCommandInterface
+class MajorUpdate extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var \Flarum\User\User
      */
diff --git a/extensions/package-manager/src/Command/MinorUpdate.php b/extensions/package-manager/src/Command/MinorUpdate.php
index 536f88339..e1cb08101 100755
--- a/extensions/package-manager/src/Command/MinorUpdate.php
+++ b/extensions/package-manager/src/Command/MinorUpdate.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class MinorUpdate implements BusinessCommandInterface
+class MinorUpdate extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var \Flarum\User\User
      */
diff --git a/extensions/package-manager/src/Command/RemoveExtension.php b/extensions/package-manager/src/Command/RemoveExtension.php
index 8f2677adf..853585dad 100755
--- a/extensions/package-manager/src/Command/RemoveExtension.php
+++ b/extensions/package-manager/src/Command/RemoveExtension.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class RemoveExtension implements BusinessCommandInterface
+class RemoveExtension extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var User
      */
diff --git a/extensions/package-manager/src/Command/RequireExtension.php b/extensions/package-manager/src/Command/RequireExtension.php
index 2741cb9fd..88bc1b975 100755
--- a/extensions/package-manager/src/Command/RequireExtension.php
+++ b/extensions/package-manager/src/Command/RequireExtension.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class RequireExtension implements BusinessCommandInterface
+class RequireExtension extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var User
      */
diff --git a/extensions/package-manager/src/Command/UpdateExtension.php b/extensions/package-manager/src/Command/UpdateExtension.php
index 7b4344ad7..cf74c484c 100755
--- a/extensions/package-manager/src/Command/UpdateExtension.php
+++ b/extensions/package-manager/src/Command/UpdateExtension.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class UpdateExtension implements BusinessCommandInterface
+class UpdateExtension extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var User
      */
diff --git a/extensions/package-manager/src/Command/WhyNot.php b/extensions/package-manager/src/Command/WhyNot.php
index 5c0b4fecc..4e2d0fc2a 100755
--- a/extensions/package-manager/src/Command/WhyNot.php
+++ b/extensions/package-manager/src/Command/WhyNot.php
@@ -12,13 +12,8 @@ namespace Flarum\PackageManager\Command;
 use Flarum\PackageManager\Task\Task;
 use Flarum\User\User;
 
-class WhyNot implements BusinessCommandInterface
+class WhyNot extends AbstractActionCommand
 {
-    /**
-     * @var Task
-     */
-    public $task = null;
-
     /**
      * @var User
      */
diff --git a/extensions/package-manager/src/Composer/ComposerAdapter.php b/extensions/package-manager/src/Composer/ComposerAdapter.php
index a678435f4..1902735ce 100644
--- a/extensions/package-manager/src/Composer/ComposerAdapter.php
+++ b/extensions/package-manager/src/Composer/ComposerAdapter.php
@@ -60,6 +60,7 @@ class ComposerAdapter
         $exitCode = $this->application->run($input, $this->output);
         chdir($currDir);
 
+        // @phpstan-ignore-next-line
         $command = $input->__toString();
         $output = $this->output->fetch();
 
diff --git a/extensions/package-manager/src/Job/ComposerCommandJob.php b/extensions/package-manager/src/Job/ComposerCommandJob.php
index 4fb6fe8a4..be9e2140f 100644
--- a/extensions/package-manager/src/Job/ComposerCommandJob.php
+++ b/extensions/package-manager/src/Job/ComposerCommandJob.php
@@ -10,7 +10,7 @@
 namespace Flarum\PackageManager\Job;
 
 use Flarum\Bus\Dispatcher;
-use Flarum\PackageManager\Command\BusinessCommandInterface;
+use Flarum\PackageManager\Command\AbstractActionCommand;
 use Flarum\PackageManager\Composer\ComposerAdapter;
 use Flarum\Queue\AbstractJob;
 use Illuminate\Queue\Middleware\WithoutOverlapping;
@@ -19,7 +19,7 @@ use Throwable;
 class ComposerCommandJob extends AbstractJob
 {
     /**
-     * @var BusinessCommandInterface
+     * @var AbstractActionCommand
      */
     protected $command;
 
@@ -28,7 +28,7 @@ class ComposerCommandJob extends AbstractJob
      */
     protected $phpVersion;
 
-    public function __construct(BusinessCommandInterface $command, string $phpVersion)
+    public function __construct(AbstractActionCommand $command, string $phpVersion)
     {
         $this->command = $command;
         $this->phpVersion = $phpVersion;
diff --git a/extensions/package-manager/src/Job/Dispatcher.php b/extensions/package-manager/src/Job/Dispatcher.php
index e5dd37864..20026dc07 100644
--- a/extensions/package-manager/src/Job/Dispatcher.php
+++ b/extensions/package-manager/src/Job/Dispatcher.php
@@ -10,7 +10,7 @@
 namespace Flarum\PackageManager\Job;
 
 use Flarum\Bus\Dispatcher as Bus;
-use Flarum\PackageManager\Command\BusinessCommandInterface;
+use Flarum\PackageManager\Command\AbstractActionCommand;
 use Flarum\PackageManager\Task\Task;
 use Flarum\Settings\SettingsRepositoryInterface;
 use Illuminate\Contracts\Queue\Queue;
@@ -63,7 +63,7 @@ class Dispatcher
         return $this;
     }
 
-    public function dispatch(BusinessCommandInterface $command): DispatcherResponse
+    public function dispatch(AbstractActionCommand $command): DispatcherResponse
     {
         $queueJobs = ($this->runSyncOverride === false) || ($this->runSyncOverride !== true && $this->settings->get('flarum-package-manager.queue_jobs'));
 
diff --git a/extensions/package-manager/src/Settings/LastUpdateRun.php b/extensions/package-manager/src/Settings/LastUpdateRun.php
index e37b8d9c1..4a21f9f14 100644
--- a/extensions/package-manager/src/Settings/LastUpdateRun.php
+++ b/extensions/package-manager/src/Settings/LastUpdateRun.php
@@ -26,7 +26,7 @@ class LastUpdateRun implements JsonSetting
     protected $data;
 
     /**
-     * @var {'major'|'minor'|'global'}
+     * @var string|null
      */
     protected $activeUpdate;
 
diff --git a/extensions/package-manager/src/Task/Task.php b/extensions/package-manager/src/Task/Task.php
index ec4bc3e66..9ce2f16d7 100644
--- a/extensions/package-manager/src/Task/Task.php
+++ b/extensions/package-manager/src/Task/Task.php
@@ -13,16 +13,16 @@ use Carbon\Carbon;
 use Flarum\Database\AbstractModel;
 
 /**
- * @property int id
- * @property int status
- * @property string operation
- * @property string command
- * @property string package
- * @property string output
- * @property Carbon created_at
- * @property Carbon started_at
- * @property Carbon finished_at
- * @property int peak_memory_used
+ * @property int $id
+ * @property int $status
+ * @property string $operation
+ * @property string $command
+ * @property string $package
+ * @property string $output
+ * @property Carbon $created_at
+ * @property Carbon $started_at
+ * @property Carbon $finished_at
+ * @property float $peak_memory_used
  */
 class Task extends AbstractModel
 {
diff --git a/extensions/pusher/src/Api/Controller/AuthController.php b/extensions/pusher/src/Api/Controller/AuthController.php
index 8fac2c880..fa95c6d8f 100644
--- a/extensions/pusher/src/Api/Controller/AuthController.php
+++ b/extensions/pusher/src/Api/Controller/AuthController.php
@@ -48,6 +48,7 @@ class AuthController implements RequestHandlerInterface
                 $this->settings->get('flarum-pusher.app_key'),
                 $this->settings->get('flarum-pusher.app_secret'),
                 $this->settings->get('flarum-pusher.app_id'),
+                // @phpstan-ignore-next-line
                 ['cluster' => $this->settings->get('flarum-pusher.app_cluster')]
             );
 
diff --git a/extensions/pusher/src/Listener/PushNewPost.php b/extensions/pusher/src/Listener/PushNewPost.php
index 851b14251..390946c25 100644
--- a/extensions/pusher/src/Listener/PushNewPost.php
+++ b/extensions/pusher/src/Listener/PushNewPost.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Pusher\Listener;
 
+use Flarum\Extension\ExtensionManager;
 use Flarum\Post\Event\Posted;
 use Flarum\User\Guest;
 use Flarum\User\User;
@@ -22,9 +23,15 @@ class PushNewPost
      */
     protected $pusher;
 
-    public function __construct(Pusher $pusher)
+    /**
+     * @var ExtensionManager
+     */
+    protected $extensions;
+
+    public function __construct(Pusher $pusher, ExtensionManager $extensions)
     {
         $this->pusher = $pusher;
+        $this->extensions = $extensions;
     }
 
     public function handle(Posted $event)
@@ -43,6 +50,7 @@ class PushNewPost
                 return;
             }
 
+            // @phpstan-ignore-next-line
             foreach ($response->channels as $name => $channel) {
                 $userId = Str::after($name, 'private-user');
 
@@ -53,7 +61,7 @@ class PushNewPost
         }
 
         if (count($channels)) {
-            $tags = $event->post->discussion->tags;
+            $tags = $this->extensions->isEnabled('flarum-tags') ? $event->post->discussion->tags : null;
 
             $this->pusher->trigger($channels, 'newPost', [
                 'postId' => $event->post->id,
diff --git a/extensions/pusher/src/Provider/PusherProvider.php b/extensions/pusher/src/Provider/PusherProvider.php
index 11efb7f23..18129516b 100644
--- a/extensions/pusher/src/Provider/PusherProvider.php
+++ b/extensions/pusher/src/Provider/PusherProvider.php
@@ -29,6 +29,7 @@ class PusherProvider extends AbstractServiceProvider
                 $settings->get('flarum-pusher.app_key'),
                 $settings->get('flarum-pusher.app_secret'),
                 $settings->get('flarum-pusher.app_id'),
+                // @phpstan-ignore-next-line
                 $options
             );
         });
diff --git a/extensions/sticky/extend.php b/extensions/sticky/extend.php
index 3e952c99c..5e08a4a08 100644
--- a/extensions/sticky/extend.php
+++ b/extensions/sticky/extend.php
@@ -9,6 +9,7 @@
 
 use Flarum\Api\Controller\ListDiscussionsController;
 use Flarum\Api\Serializer\DiscussionSerializer;
+use Flarum\Discussion\Discussion;
 use Flarum\Discussion\Event\Saving;
 use Flarum\Discussion\Filter\DiscussionFilterer;
 use Flarum\Discussion\Search\DiscussionSearcher;
@@ -26,6 +27,9 @@ return [
         ->js(__DIR__.'/js/dist/forum.js')
         ->css(__DIR__.'/less/forum.less'),
 
+    (new Extend\Model(Discussion::class))
+        ->cast('is_sticky', 'bool'),
+
     (new Extend\Post())
         ->type(DiscussionStickiedPost::class),
 
diff --git a/extensions/sticky/src/PinStickiedDiscussionsToTop.php b/extensions/sticky/src/PinStickiedDiscussionsToTop.php
index 22757dfa4..44e956204 100755
--- a/extensions/sticky/src/PinStickiedDiscussionsToTop.php
+++ b/extensions/sticky/src/PinStickiedDiscussionsToTop.php
@@ -43,12 +43,12 @@ class PinStickiedDiscussionsToTop
             // reorder the unread ones up to the top.
             $sticky = clone $query;
             $sticky->where('is_sticky', true);
-            $sticky->orders = null;
+            unset($sticky->orders);
 
             $query->union($sticky);
 
             $read = $query->newQuery()
-                ->selectRaw(1)
+                ->selectRaw('1')
                 ->from('discussion_user as sticky')
                 ->whereColumn('sticky.discussion_id', 'id')
                 ->where('sticky.user_id', '=', $filterState->getActor()->id)
@@ -58,14 +58,14 @@ class PinStickiedDiscussionsToTop
             // argument in orderByRaw) for now due to a bug in Laravel which
             // would add the bindings in the wrong order.
             $query->orderByRaw('is_sticky and not exists ('.$read->toSql().') and last_posted_at > ? desc')
-                ->addBinding(array_merge($read->getBindings(), [$filterState->getActor()->read_time ?: 0]), 'union');
+                ->addBinding(array_merge($read->getBindings(), [$filterState->getActor()->marked_all_as_read_at ?: 0]), 'union');
 
             $query->unionOrders = array_merge($query->unionOrders, $query->orders);
             $query->unionLimit = $query->limit;
             $query->unionOffset = $query->offset;
 
             $query->limit = $sticky->limit = $query->offset + $query->limit;
-            $query->offset = $sticky->offset = null;
+            unset($query->offset, $sticky->offset);
         }
     }
 }
diff --git a/extensions/sticky/src/Post/DiscussionStickiedPost.php b/extensions/sticky/src/Post/DiscussionStickiedPost.php
index c9204b1e0..c6a1c1f0c 100755
--- a/extensions/sticky/src/Post/DiscussionStickiedPost.php
+++ b/extensions/sticky/src/Post/DiscussionStickiedPost.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Sticky\Post;
 
+use Carbon\Carbon;
 use Flarum\Post\AbstractEventPost;
 use Flarum\Post\MergeableInterface;
 use Flarum\Post\Post;
@@ -59,7 +60,7 @@ class DiscussionStickiedPost extends AbstractEventPost implements MergeableInter
         $post = new static;
 
         $post->content = static::buildContent($isSticky);
-        $post->created_at = time();
+        $post->created_at = Carbon::now();
         $post->discussion_id = $discussionId;
         $post->user_id = $userId;
 
diff --git a/extensions/subscriptions/extend.php b/extensions/subscriptions/extend.php
index e39da0de5..468265cc1 100644
--- a/extensions/subscriptions/extend.php
+++ b/extensions/subscriptions/extend.php
@@ -14,6 +14,7 @@ use Flarum\Discussion\Discussion;
 use Flarum\Discussion\Event\Saving;
 use Flarum\Discussion\Filter\DiscussionFilterer;
 use Flarum\Discussion\Search\DiscussionSearcher;
+use Flarum\Discussion\UserState;
 use Flarum\Extend;
 use Flarum\Post\Event\Deleted;
 use Flarum\Post\Event\Hidden;
@@ -24,6 +25,7 @@ use Flarum\Subscriptions\Listener;
 use Flarum\Subscriptions\Notification\FilterVisiblePostsBeforeSending;
 use Flarum\Subscriptions\Notification\NewPostBlueprint;
 use Flarum\Subscriptions\Query\SubscriptionFilterGambit;
+use Flarum\User\User;
 
 return [
     (new Extend\Frontend('forum'))
@@ -33,6 +35,12 @@ return [
 
     new Extend\Locales(__DIR__.'/locale'),
 
+    (new Extend\Model(User::class))
+        ->cast('last_read_post_number', 'integer'),
+
+    (new Extend\Model(UserState::class))
+        ->cast('subscription', 'string'),
+
     (new Extend\View)
         ->namespace('flarum-subscriptions', __DIR__.'/views'),
 
diff --git a/extensions/suspend/extend.php b/extensions/suspend/extend.php
index 7e66e7609..fe924d00b 100644
--- a/extensions/suspend/extend.php
+++ b/extensions/suspend/extend.php
@@ -34,7 +34,9 @@ return [
         ->css(__DIR__.'/less/admin.less'),
 
     (new Extend\Model(User::class))
-        ->dateAttribute('suspended_until'),
+        ->cast('suspended_until', 'datetime')
+        ->cast('suspend_reason', 'string')
+        ->cast('suspend_message', 'string'),
 
     (new Extend\ApiSerializer(UserSerializer::class))
         ->attributes(AddUserSuspendAttributes::class),
diff --git a/extensions/suspend/src/Listener/SaveSuspensionToDatabase.php b/extensions/suspend/src/Listener/SaveSuspensionToDatabase.php
index 59f4d452e..a516398d9 100755
--- a/extensions/suspend/src/Listener/SaveSuspensionToDatabase.php
+++ b/extensions/suspend/src/Listener/SaveSuspensionToDatabase.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Suspend\Listener;
 
+use Carbon\Carbon;
 use DateTime;
 use Flarum\Suspend\Event\Suspended;
 use Flarum\Suspend\Event\Unsuspended;
@@ -54,7 +55,7 @@ class SaveSuspensionToDatabase
             $actor->assertCan('suspend', $user);
 
             if ($attributes['suspendedUntil']) {
-                $user->suspended_until = new DateTime($attributes['suspendedUntil']);
+                $user->suspended_until = Carbon::createFromTimestamp((new DateTime($attributes['suspendedUntil']))->getTimestamp());
                 $user->suspend_reason = empty($attributes['suspendReason']) ? null : $attributes['suspendReason'];
                 $user->suspend_message = empty($attributes['suspendMessage']) ? null : $attributes['suspendMessage'];
             } else {
diff --git a/extensions/tags/src/Access/DiscussionPolicy.php b/extensions/tags/src/Access/DiscussionPolicy.php
index 70fb9400d..a4cfccc64 100755
--- a/extensions/tags/src/Access/DiscussionPolicy.php
+++ b/extensions/tags/src/Access/DiscussionPolicy.php
@@ -34,7 +34,7 @@ class DiscussionPolicy extends AbstractPolicy
      * @param User $actor
      * @param string $ability
      * @param Discussion $discussion
-     * @return bool
+     * @return string|void
      */
     public function can(User $actor, $ability, Discussion $discussion)
     {
@@ -68,7 +68,7 @@ class DiscussionPolicy extends AbstractPolicy
      *
      * @param User $actor
      * @param Discussion $discussion
-     * @return bool
+     * @return string|void
      */
     public function tag(User $actor, Discussion $discussion)
     {
diff --git a/extensions/tags/src/Access/GlobalPolicy.php b/extensions/tags/src/Access/GlobalPolicy.php
index 5c3a27c52..feb05432a 100644
--- a/extensions/tags/src/Access/GlobalPolicy.php
+++ b/extensions/tags/src/Access/GlobalPolicy.php
@@ -27,9 +27,9 @@ class GlobalPolicy extends AbstractPolicy
     }
 
     /**
-     * @param Flarum\User\User $actor
+     * @param User $actor
      * @param string $ability
-     * @return bool|void
+     * @return string|void
      */
     public function can(User $actor, string $ability)
     {
diff --git a/extensions/tags/src/Api/Serializer/TagSerializer.php b/extensions/tags/src/Api/Serializer/TagSerializer.php
index 7316ae511..a989061cb 100644
--- a/extensions/tags/src/Api/Serializer/TagSerializer.php
+++ b/extensions/tags/src/Api/Serializer/TagSerializer.php
@@ -13,6 +13,7 @@ use Flarum\Api\Serializer\AbstractSerializer;
 use Flarum\Api\Serializer\DiscussionSerializer;
 use Flarum\Http\SlugManager;
 use Flarum\Tags\Tag;
+use InvalidArgumentException;
 
 class TagSerializer extends AbstractSerializer
 {
@@ -39,6 +40,12 @@ class TagSerializer extends AbstractSerializer
      */
     protected function getDefaultAttributes($tag)
     {
+        if (! ($tag instanceof Tag)) {
+            throw new InvalidArgumentException(
+                get_class($this).' can only serialize instances of '.Tag::class
+            );
+        }
+
         $attributes = [
             'name'               => $tag->name,
             'description'        => $tag->description,
diff --git a/extensions/tags/src/Listener/UpdateTagMetadata.php b/extensions/tags/src/Listener/UpdateTagMetadata.php
index 9fac2d079..f0f0132ed 100755
--- a/extensions/tags/src/Listener/UpdateTagMetadata.php
+++ b/extensions/tags/src/Listener/UpdateTagMetadata.php
@@ -18,9 +18,11 @@ use Flarum\Post\Event\Deleted as PostDeleted;
 use Flarum\Post\Event\Hidden as PostHidden;
 use Flarum\Post\Event\Posted;
 use Flarum\Post\Event\Restored as PostRestored;
+use Flarum\Post\Post;
 use Flarum\Tags\Event\DiscussionWasTagged;
 use Flarum\Tags\Tag;
 use Illuminate\Contracts\Events\Dispatcher;
+use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Support\Arr;
 
 class UpdateTagMetadata
@@ -124,9 +126,9 @@ class UpdateTagMetadata
     }
 
     /**
-     * @param \Flarum\Discussion\Discussion $discussion
+     * @param Discussion $discussion
      * @param int $delta
-     * @param Tag[]|null $tags
+     * @param Collection<Tag>|null $tags
      * @param Post $post: This is only used when a post has been hidden
      */
     protected function updateTags(Discussion $discussion, $delta = 0, $tags = null, $post = null)
diff --git a/extensions/tags/src/Post/DiscussionTaggedPost.php b/extensions/tags/src/Post/DiscussionTaggedPost.php
index 043697a4c..0dd458703 100755
--- a/extensions/tags/src/Post/DiscussionTaggedPost.php
+++ b/extensions/tags/src/Post/DiscussionTaggedPost.php
@@ -9,6 +9,7 @@
 
 namespace Flarum\Tags\Post;
 
+use Carbon\Carbon;
 use Flarum\Post\AbstractEventPost;
 use Flarum\Post\MergeableInterface;
 use Flarum\Post\Post;
@@ -61,7 +62,7 @@ class DiscussionTaggedPost extends AbstractEventPost implements MergeableInterfa
         $post = new static;
 
         $post->content = static::buildContent($oldTagIds, $newTagIds);
-        $post->created_at = time();
+        $post->created_at = Carbon::now();
         $post->discussion_id = $discussionId;
         $post->user_id = $userId;
 
diff --git a/extensions/tags/src/Query/TagFilterGambit.php b/extensions/tags/src/Query/TagFilterGambit.php
index 1dea31f16..6d8a6719e 100644
--- a/extensions/tags/src/Query/TagFilterGambit.php
+++ b/extensions/tags/src/Query/TagFilterGambit.php
@@ -38,7 +38,7 @@ class TagFilterGambit extends AbstractRegexGambit implements FilterInterface
 
     protected function conditions(SearchState $search, array $matches, $negate)
     {
-        $this->constrain($search->getQuery(), $matches[1], $negate);
+        $this->constrain($search->getQuery(), $matches[1], $negate, $search->getActor());
     }
 
     public function getFilterKey(): string
diff --git a/extensions/tags/src/Tag.php b/extensions/tags/src/Tag.php
index 202a54a1b..2bcbab5c1 100644
--- a/extensions/tags/src/Tag.php
+++ b/extensions/tags/src/Tag.php
@@ -15,6 +15,7 @@ use Flarum\Discussion\Discussion;
 use Flarum\Group\Permission;
 use Flarum\User\User;
 use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Collection;
 
 /**
  * @property int $id
@@ -34,7 +35,13 @@ use Illuminate\Database\Eloquent\Builder;
  * @property int $last_posted_discussion_id
  * @property int $last_posted_user_id
  * @property string $icon
- * @property TagState
+ *
+ * @property TagState $state
+ * @property Tag|null $parent
+ * @property-read Collection<Tag> $children
+ * @property-read Collection<Discussion> $discussions
+ * @property Discussion|null $lastPostedDiscussion
+ * @property User|null $lastPostedUser
  */
 class Tag extends AbstractModel
 {
diff --git a/extensions/tags/src/TagRepository.php b/extensions/tags/src/TagRepository.php
index 0ae910eaf..3997d2850 100644
--- a/extensions/tags/src/TagRepository.php
+++ b/extensions/tags/src/TagRepository.php
@@ -29,7 +29,7 @@ class TagRepository
     /**
      * @param array|string $relations
      * @param User $actor
-     * @return Builder
+     * @return Builder<Tag>
      */
     public function with($relations, User $actor): Builder
     {
@@ -64,9 +64,8 @@ class TagRepository
      * user, or throw an exception.
      *
      * @param int $id
-     * @param User $actor
+     * @param User|null $actor
      * @return Tag
-     * @throws \Illuminate\Database\Eloquent\ModelNotFoundException
      */
     public function findOrFail($id, User $actor = null)
     {
@@ -80,7 +79,7 @@ class TagRepository
      * certain user.
      *
      * @param User|null $user
-     * @return \Illuminate\Database\Eloquent\Collection
+     * @return \Illuminate\Database\Eloquent\Collection<Tag>
      */
     public function all(User $user = null)
     {
@@ -106,9 +105,9 @@ class TagRepository
     /**
      * Scope a query to only include records that are visible to a user.
      *
-     * @param Builder $query
-     * @param User $user
-     * @return Builder
+     * @param Builder<Tag> $query
+     * @param User|null $user
+     * @return Builder<Tag>
      */
     protected function scopeVisibleTo(Builder $query, User $user = null)
     {
diff --git a/extensions/tags/src/Utf8SlugDriver.php b/extensions/tags/src/Utf8SlugDriver.php
index aef92f4fe..36df9c9e4 100644
--- a/extensions/tags/src/Utf8SlugDriver.php
+++ b/extensions/tags/src/Utf8SlugDriver.php
@@ -44,10 +44,13 @@ class Utf8SlugDriver implements SlugDriverInterface
      */
     public function fromSlug(string $slug, User $actor): AbstractModel
     {
-        return $this->repository
+        /** @var Tag $tag */
+        $tag = $this->repository
             ->query()
             ->where('slug', urldecode($slug))
             ->whereVisibleTo($actor)
             ->firstOrFail();
+
+        return $tag;
     }
 }
diff --git a/framework/core/src/Extend/Validator.php b/framework/core/src/Extend/Validator.php
index 817367c00..0420b0e2b 100644
--- a/framework/core/src/Extend/Validator.php
+++ b/framework/core/src/Extend/Validator.php
@@ -31,7 +31,7 @@ class Validator implements ExtenderInterface
      * Configure the validator. This is often used to adjust validation rules, but can be
      * used to make other changes to the validator as well.
      *
-     * @param callable $callback
+     * @param callable|class-string $callback
      *
      * The callback can be a closure or invokable class, and should accept:
      * - \Flarum\Foundation\AbstractValidator $flarumValidator: The Flarum validator wrapper
diff --git a/framework/core/src/Extension/Extension.php b/framework/core/src/Extension/Extension.php
index 6856d9214..15892470e 100644
--- a/framework/core/src/Extension/Extension.php
+++ b/framework/core/src/Extension/Extension.php
@@ -236,7 +236,7 @@ class Extension implements Arrayable
     }
 
     /**
-     * @return string
+     * @return string|null
      */
     public function getVersion()
     {
diff --git a/framework/core/src/Notification/Blueprint/BlueprintInterface.php b/framework/core/src/Notification/Blueprint/BlueprintInterface.php
index 38f5ed060..caae87e41 100644
--- a/framework/core/src/Notification/Blueprint/BlueprintInterface.php
+++ b/framework/core/src/Notification/Blueprint/BlueprintInterface.php
@@ -36,7 +36,7 @@ interface BlueprintInterface
     /**
      * Get the data to be stored in the notification.
      *
-     * @return array|null
+     * @return mixed
      */
     public function getData();
 
diff --git a/framework/core/src/Notification/MailableInterface.php b/framework/core/src/Notification/MailableInterface.php
index 2804e0704..f95b17a9b 100644
--- a/framework/core/src/Notification/MailableInterface.php
+++ b/framework/core/src/Notification/MailableInterface.php
@@ -16,7 +16,7 @@ interface MailableInterface
     /**
      * Get the name of the view to construct a notification email with.
      *
-     * @return string
+     * @return string|array
      */
     public function getEmailView();
 
diff --git a/framework/core/src/Post/Event/Posted.php b/framework/core/src/Post/Event/Posted.php
index 104fbff1f..158e6a55b 100644
--- a/framework/core/src/Post/Event/Posted.php
+++ b/framework/core/src/Post/Event/Posted.php
@@ -9,25 +9,26 @@
 
 namespace Flarum\Post\Event;
 
-use Flarum\Post\Post;
+use Flarum\Post\CommentPost;
 use Flarum\User\User;
 
 class Posted
 {
     /**
-     * @var \Flarum\Post\Post
+     * @var CommentPost
      */
     public $post;
 
     /**
-     * @var User
+     * @var User|null
      */
     public $actor;
 
     /**
-     * @param \Flarum\Post\Post $post
+     * @param CommentPost $post
+     * @param User|null $actor
      */
-    public function __construct(Post $post, User $actor = null)
+    public function __construct(CommentPost $post, User $actor = null)
     {
         $this->post = $post;
         $this->actor = $actor;
diff --git a/phpstan.neon b/phpstan.neon
index 5c5b81eb4..5081c1bac 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -5,6 +5,34 @@ parameters:
 	level: 5
 	paths:
 	  - framework/core/src
+	  - extensions/akismet/src
+	  - extensions/akismet/extend.php
+	  - extensions/approval/src
+	  - extensions/approval/extend.php
+	  - extensions/flags/src
+	  - extensions/flags/extend.php
+	  - extensions/likes/src
+	  - extensions/likes/extend.php
+	  - extensions/lock/src
+	  - extensions/lock/extend.php
+	  - extensions/mentions/src
+	  - extensions/mentions/extend.php
+	  - extensions/nicknames/src
+	  - extensions/nicknames/extend.php
+	  - extensions/package-manager/src
+	  - extensions/package-manager/extend.php
+	  - extensions/pusher/src
+	  - extensions/pusher/extend.php
+	  - extensions/statistics/src
+	  - extensions/statistics/extend.php
+	  - extensions/sticky/src
+	  - extensions/sticky/extend.php
+	  - extensions/subscriptions/src
+	  - extensions/subscriptions/extend.php
+	  - extensions/suspend/src
+	  - extensions/suspend/extend.php
+	  - extensions/tags/src
+	  - extensions/tags/extend.php
 	excludePaths:
 		- *.blade.php
 	checkMissingIterableValueType: false