diff --git a/app/Http/Controllers/Account/IndexController.php b/app/Http/Controllers/Account/IndexController.php
index 0bfaec642b..bbc4fd602f 100644
--- a/app/Http/Controllers/Account/IndexController.php
+++ b/app/Http/Controllers/Account/IndexController.php
@@ -194,7 +194,7 @@ class IndexController extends Controller
         return view('accounts.index', compact('objectType', 'inactiveCount', 'subTitleIcon', 'subTitle', 'page', 'accounts'));
     }
 
-    private function subtract(array $startBalances, array $endBalances)
+    private function subtract(array $startBalances, array $endBalances): array
     {
         $result = [];
         foreach ($endBalances as $key => $value) {
diff --git a/app/Http/Controllers/Admin/NotificationController.php b/app/Http/Controllers/Admin/NotificationController.php
index 91a9f42c6d..fb16ac7c74 100644
--- a/app/Http/Controllers/Admin/NotificationController.php
+++ b/app/Http/Controllers/Admin/NotificationController.php
@@ -31,10 +31,11 @@ use FireflyIII\Notifications\Notifiables\OwnerNotifiable;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Log;
+use Illuminate\View\View;
 
 class NotificationController extends Controller
 {
-    public function index()
+    public function index(): View
     {
         Log::channel('audit')->info('User visits notifications index.');
         $title                          = (string) trans('firefly.administration');
diff --git a/app/Notifications/Admin/UnknownUserLoginAttempt.php b/app/Notifications/Admin/UnknownUserLoginAttempt.php
index 6fa01590fe..b19dd53ad6 100644
--- a/app/Notifications/Admin/UnknownUserLoginAttempt.php
+++ b/app/Notifications/Admin/UnknownUserLoginAttempt.php
@@ -50,7 +50,7 @@ class UnknownUserLoginAttempt extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(OwnerNotifiable $notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -109,7 +109,7 @@ class UnknownUserLoginAttempt extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('owner');
     }
diff --git a/app/Notifications/Admin/UserInvitation.php b/app/Notifications/Admin/UserInvitation.php
index d348f08247..eed76f98a3 100644
--- a/app/Notifications/Admin/UserInvitation.php
+++ b/app/Notifications/Admin/UserInvitation.php
@@ -55,7 +55,7 @@ class UserInvitation extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(OwnerNotifiable $notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -64,7 +64,7 @@ class UserInvitation extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(OwnerNotifiable $notifiable)
+    public function toMail(OwnerNotifiable $notifiable): MailMessage
     {
         $ip        = Request::ip();
         $host      = Steam::getHostName($ip);
@@ -108,7 +108,7 @@ class UserInvitation extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(OwnerNotifiable $notifiable)
+    public function toSlack(OwnerNotifiable $notifiable): SlackMessage
     {
         return new SlackMessage()->content(
             (string) trans('email.invitation_created_body', ['email' => $this->invitee->user->email, 'invitee' => $this->invitee->email])
@@ -118,7 +118,7 @@ class UserInvitation extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('owner');
     }
diff --git a/app/Notifications/Admin/UserRegistration.php b/app/Notifications/Admin/UserRegistration.php
index 8e896a8fd0..9fbd1ea148 100644
--- a/app/Notifications/Admin/UserRegistration.php
+++ b/app/Notifications/Admin/UserRegistration.php
@@ -55,7 +55,7 @@ class UserRegistration extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(OwnerNotifiable $notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -64,7 +64,7 @@ class UserRegistration extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(OwnerNotifiable $notifiable)
+    public function toMail(OwnerNotifiable $notifiable): MailMessage
     {
         $ip        = Request::ip();
         $host      = Steam::getHostName($ip);
@@ -107,7 +107,7 @@ class UserRegistration extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(OwnerNotifiable $notifiable)
+    public function toSlack(OwnerNotifiable $notifiable): SlackMessage
     {
         return new SlackMessage()->content((string) trans('email.admin_new_user_registered', ['email' => $this->user->email, 'id' => $this->user->id]));
     }
@@ -115,7 +115,7 @@ class UserRegistration extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('owner');
     }
diff --git a/app/Notifications/Admin/VersionCheckResult.php b/app/Notifications/Admin/VersionCheckResult.php
index 3408257e4a..d966313d45 100644
--- a/app/Notifications/Admin/VersionCheckResult.php
+++ b/app/Notifications/Admin/VersionCheckResult.php
@@ -52,7 +52,7 @@ class VersionCheckResult extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(OwnerNotifiable $notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -61,7 +61,7 @@ class VersionCheckResult extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(OwnerNotifiable $notifiable)
+    public function toMail(OwnerNotifiable $notifiable): MailMessage
     {
         return (new MailMessage())
             ->markdown('emails.new-version', ['message' => $this->message])
@@ -99,7 +99,7 @@ class VersionCheckResult extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(OwnerNotifiable $notifiable)
+    public function toSlack(OwnerNotifiable $notifiable): SlackMessage
     {
         return new SlackMessage()->content($this->message)
             ->attachment(static function ($attachment): void {
@@ -111,7 +111,7 @@ class VersionCheckResult extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('owner');
     }
diff --git a/app/Notifications/Notifiables/OwnerNotifiable.php b/app/Notifications/Notifiables/OwnerNotifiable.php
index 300dd427fd..96198c5d39 100644
--- a/app/Notifications/Notifiables/OwnerNotifiable.php
+++ b/app/Notifications/Notifiables/OwnerNotifiable.php
@@ -55,7 +55,7 @@ class OwnerNotifiable
         };
     }
 
-    public function routeNotificationForPushover()
+    public function routeNotificationForPushover(): PushoverReceiver
     {
         Log::debug('Return settings for routeNotificationForPushover');
         $pushoverAppToken  = (string) app('fireflyconfig')->getEncrypted('pushover_app_token', '')->data;
diff --git a/app/Notifications/ReturnsSettings.php b/app/Notifications/ReturnsSettings.php
index 40b918d37d..2b8adb162a 100644
--- a/app/Notifications/ReturnsSettings.php
+++ b/app/Notifications/ReturnsSettings.php
@@ -40,7 +40,7 @@ class ReturnsSettings
         throw new FireflyException(sprintf('Cannot handle channel "%s"', $channel));
     }
 
-    private static function getNtfySettings(string $type, ?User $user)
+    private static function getNtfySettings(string $type, ?User $user): array
     {
         $settings = [
             'ntfy_server' => 'https://ntfy.sh',
diff --git a/app/Notifications/Security/DisabledMFANotification.php b/app/Notifications/Security/DisabledMFANotification.php
index f5b7af8c63..991d98d7e8 100644
--- a/app/Notifications/Security/DisabledMFANotification.php
+++ b/app/Notifications/Security/DisabledMFANotification.php
@@ -50,7 +50,7 @@ class DisabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -59,7 +59,7 @@ class DisabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.disabled_mfa_subject');
         $ip        = Request::ip();
@@ -94,7 +94,7 @@ class DisabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.disabled_mfa_slack', ['email' => $this->user->email]);
 
@@ -104,7 +104,7 @@ class DisabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Security/EnabledMFANotification.php b/app/Notifications/Security/EnabledMFANotification.php
index 3074c89121..dea2facf36 100644
--- a/app/Notifications/Security/EnabledMFANotification.php
+++ b/app/Notifications/Security/EnabledMFANotification.php
@@ -50,7 +50,7 @@ class EnabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -59,7 +59,7 @@ class EnabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.enabled_mfa_subject');
         $ip        = Request::ip();
@@ -94,7 +94,7 @@ class EnabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.enabled_mfa_slack', ['email' => $this->user->email]);
 
@@ -104,7 +104,7 @@ class EnabledMFANotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Security/MFABackupFewLeftNotification.php b/app/Notifications/Security/MFABackupFewLeftNotification.php
index 99f75b861c..da683b1f4e 100644
--- a/app/Notifications/Security/MFABackupFewLeftNotification.php
+++ b/app/Notifications/Security/MFABackupFewLeftNotification.php
@@ -52,7 +52,7 @@ class MFABackupFewLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -61,7 +61,7 @@ class MFABackupFewLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.mfa_few_backups_left_subject', ['count' => $this->count]);
         $ip        = Request::ip();
@@ -96,7 +96,7 @@ class MFABackupFewLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.mfa_few_backups_left_slack', ['email' => $this->user->email, 'count' => $this->count]);
 
@@ -106,7 +106,7 @@ class MFABackupFewLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Security/MFABackupNoLeftNotification.php b/app/Notifications/Security/MFABackupNoLeftNotification.php
index bcbd8d0cfb..5bea9e6aa2 100644
--- a/app/Notifications/Security/MFABackupNoLeftNotification.php
+++ b/app/Notifications/Security/MFABackupNoLeftNotification.php
@@ -50,7 +50,7 @@ class MFABackupNoLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -59,7 +59,7 @@ class MFABackupNoLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.mfa_no_backups_left_subject');
         $ip        = Request::ip();
@@ -94,7 +94,7 @@ class MFABackupNoLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.mfa_no_backups_left_slack', ['email' => $this->user->email]);
 
@@ -104,7 +104,7 @@ class MFABackupNoLeftNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Security/MFAManyFailedAttemptsNotification.php b/app/Notifications/Security/MFAManyFailedAttemptsNotification.php
index 17638358c7..781bf62e95 100644
--- a/app/Notifications/Security/MFAManyFailedAttemptsNotification.php
+++ b/app/Notifications/Security/MFAManyFailedAttemptsNotification.php
@@ -49,7 +49,7 @@ class MFAManyFailedAttemptsNotification extends Notification
         $this->count = $count;
     }
 
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -58,7 +58,7 @@ class MFAManyFailedAttemptsNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.mfa_many_failed_subject', ['count' => $this->count]);
         $ip        = Request::ip();
@@ -93,7 +93,7 @@ class MFAManyFailedAttemptsNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.mfa_many_failed_slack', ['email' => $this->user->email, 'count' => $this->count]);
 
@@ -103,7 +103,7 @@ class MFAManyFailedAttemptsNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Security/MFAUsedBackupCodeNotification.php b/app/Notifications/Security/MFAUsedBackupCodeNotification.php
index 5eba3c43c8..0b03853275 100644
--- a/app/Notifications/Security/MFAUsedBackupCodeNotification.php
+++ b/app/Notifications/Security/MFAUsedBackupCodeNotification.php
@@ -50,7 +50,7 @@ class MFAUsedBackupCodeNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -59,7 +59,7 @@ class MFAUsedBackupCodeNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.used_backup_code_subject');
         $ip        = Request::ip();
@@ -94,7 +94,7 @@ class MFAUsedBackupCodeNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.used_backup_code_slack', ['email' => $this->user->email]);
 
@@ -104,7 +104,7 @@ class MFAUsedBackupCodeNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Security/NewBackupCodesNotification.php b/app/Notifications/Security/NewBackupCodesNotification.php
index 1251c6cf88..06ef35f89e 100644
--- a/app/Notifications/Security/NewBackupCodesNotification.php
+++ b/app/Notifications/Security/NewBackupCodesNotification.php
@@ -50,7 +50,7 @@ class NewBackupCodesNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -59,7 +59,7 @@ class NewBackupCodesNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.new_backup_codes_subject');
         $ip        = Request::ip();
@@ -94,7 +94,7 @@ class NewBackupCodesNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.new_backup_codes_slack', ['email' => $this->user->email]);
 
@@ -104,7 +104,7 @@ class NewBackupCodesNotification extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Security/UserFailedLoginAttempt.php b/app/Notifications/Security/UserFailedLoginAttempt.php
index 7ed59f4127..69bb04110c 100644
--- a/app/Notifications/Security/UserFailedLoginAttempt.php
+++ b/app/Notifications/Security/UserFailedLoginAttempt.php
@@ -47,7 +47,7 @@ class UserFailedLoginAttempt extends Notification
         $this->user = $user;
     }
 
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -56,7 +56,7 @@ class UserFailedLoginAttempt extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $subject   = (string) trans('email.failed_login_subject');
         $ip        = Request::ip();
@@ -91,7 +91,7 @@ class UserFailedLoginAttempt extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $message = (string) trans('email.failed_login_message', ['email' => $this->user->email]);
 
@@ -101,7 +101,7 @@ class UserFailedLoginAttempt extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/Test/OwnerTestNotificationEmail.php b/app/Notifications/Test/OwnerTestNotificationEmail.php
index c1fd32a779..57df79296d 100644
--- a/app/Notifications/Test/OwnerTestNotificationEmail.php
+++ b/app/Notifications/Test/OwnerTestNotificationEmail.php
@@ -39,7 +39,7 @@ class OwnerTestNotificationEmail extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(OwnerNotifiable $notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -48,7 +48,7 @@ class OwnerTestNotificationEmail extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(OwnerNotifiable $notifiable)
+    public function toMail(OwnerNotifiable $notifiable): MailMessage
     {
         $address = (string) config('firefly.site_owner');
 
@@ -61,7 +61,7 @@ class OwnerTestNotificationEmail extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return ['mail'];
     }
diff --git a/app/Notifications/Test/OwnerTestNotificationNtfy.php b/app/Notifications/Test/OwnerTestNotificationNtfy.php
index 53a82e5376..9f72e8544b 100644
--- a/app/Notifications/Test/OwnerTestNotificationNtfy.php
+++ b/app/Notifications/Test/OwnerTestNotificationNtfy.php
@@ -42,10 +42,8 @@ class OwnerTestNotificationNtfy extends Notification
 
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
-     *
-     * @param mixed $notifiable
      */
-    public function toArray($notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -69,7 +67,7 @@ class OwnerTestNotificationNtfy extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return [NtfyChannel::class];
     }
diff --git a/app/Notifications/Test/OwnerTestNotificationPushover.php b/app/Notifications/Test/OwnerTestNotificationPushover.php
index 4c19060e5c..0e2c444f01 100644
--- a/app/Notifications/Test/OwnerTestNotificationPushover.php
+++ b/app/Notifications/Test/OwnerTestNotificationPushover.php
@@ -43,7 +43,7 @@ class OwnerTestNotificationPushover extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(OwnerNotifiable $notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -64,7 +64,7 @@ class OwnerTestNotificationPushover extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return [PushoverChannel::class];
     }
diff --git a/app/Notifications/Test/OwnerTestNotificationSlack.php b/app/Notifications/Test/OwnerTestNotificationSlack.php
index f243ce460f..7a0a6e40de 100644
--- a/app/Notifications/Test/OwnerTestNotificationSlack.php
+++ b/app/Notifications/Test/OwnerTestNotificationSlack.php
@@ -41,7 +41,7 @@ class OwnerTestNotificationSlack extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(OwnerNotifiable $notifiable)
+    public function toArray(OwnerNotifiable $notifiable): array
     {
         return [
         ];
@@ -50,7 +50,7 @@ class OwnerTestNotificationSlack extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(OwnerNotifiable $notifiable)
+    public function toSlack(OwnerNotifiable $notifiable): SlackMessage
     {
         return new SlackMessage()->content((string) trans('email.admin_test_subject'));
         // return new SlackMessage()->text((string) trans('email.admin_test_subject'))->to($url);
@@ -59,7 +59,7 @@ class OwnerTestNotificationSlack extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(OwnerNotifiable $notifiable)
+    public function via(OwnerNotifiable $notifiable): array
     {
         return ['slack'];
     }
diff --git a/app/Notifications/Test/UserTestNotificationEmail.php b/app/Notifications/Test/UserTestNotificationEmail.php
index aeefc9a061..07f5b42e73 100644
--- a/app/Notifications/Test/UserTestNotificationEmail.php
+++ b/app/Notifications/Test/UserTestNotificationEmail.php
@@ -39,13 +39,13 @@ class UserTestNotificationEmail extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
     }
 
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $address = (string) $notifiable->email;
 
@@ -58,7 +58,7 @@ class UserTestNotificationEmail extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ['mail'];
     }
diff --git a/app/Notifications/Test/UserTestNotificationNtfy.php b/app/Notifications/Test/UserTestNotificationNtfy.php
index b5bbf8bbea..babcb459f8 100644
--- a/app/Notifications/Test/UserTestNotificationNtfy.php
+++ b/app/Notifications/Test/UserTestNotificationNtfy.php
@@ -43,7 +43,7 @@ class UserTestNotificationNtfy extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -67,7 +67,7 @@ class UserTestNotificationNtfy extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $user)
+    public function via(User $user): array
     {
         return [NtfyChannel::class];
     }
diff --git a/app/Notifications/Test/UserTestNotificationPushover.php b/app/Notifications/Test/UserTestNotificationPushover.php
index 05e1901820..e963b4bca9 100644
--- a/app/Notifications/Test/UserTestNotificationPushover.php
+++ b/app/Notifications/Test/UserTestNotificationPushover.php
@@ -43,7 +43,7 @@ class UserTestNotificationPushover extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -64,7 +64,7 @@ class UserTestNotificationPushover extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return [PushoverChannel::class];
     }
diff --git a/app/Notifications/Test/UserTestNotificationSlack.php b/app/Notifications/Test/UserTestNotificationSlack.php
index 35febbb0d2..59cedc0b4c 100644
--- a/app/Notifications/Test/UserTestNotificationSlack.php
+++ b/app/Notifications/Test/UserTestNotificationSlack.php
@@ -41,7 +41,7 @@ class UserTestNotificationSlack extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $user)
+    public function toArray(User $user): array
     {
         return [
         ];
@@ -50,7 +50,7 @@ class UserTestNotificationSlack extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $user)
+    public function toSlack(User $user): SlackMessage
     {
         return new SlackMessage()->content((string) trans('email.admin_test_subject'));
         // return new SlackMessage()->text((string) trans('email.admin_test_subject'))->to($url);
@@ -59,7 +59,7 @@ class UserTestNotificationSlack extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $user)
+    public function via(User $user): array
     {
         return ['slack'];
     }
diff --git a/app/Notifications/User/BillReminder.php b/app/Notifications/User/BillReminder.php
index eadde2d75c..77de530d55 100644
--- a/app/Notifications/User/BillReminder.php
+++ b/app/Notifications/User/BillReminder.php
@@ -56,7 +56,7 @@ class BillReminder extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -65,7 +65,7 @@ class BillReminder extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         return (new MailMessage())
             ->markdown('emails.bill-warning', ['field' => $this->field, 'diff' => $this->diff, 'bill' => $this->bill])
@@ -107,7 +107,7 @@ class BillReminder extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $bill = $this->bill;
         $url  = route('bills.show', [$bill->id]);
@@ -124,7 +124,7 @@ class BillReminder extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/User/NewAccessToken.php b/app/Notifications/User/NewAccessToken.php
index 9e659ac40d..1634638caa 100644
--- a/app/Notifications/User/NewAccessToken.php
+++ b/app/Notifications/User/NewAccessToken.php
@@ -45,7 +45,7 @@ class NewAccessToken extends Notification
 
     public function __construct() {}
 
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -54,7 +54,7 @@ class NewAccessToken extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $ip        = Request::ip();
         $host      = Steam::getHostName($ip);
@@ -91,7 +91,7 @@ class NewAccessToken extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         return new SlackMessage()->content((string) trans('email.access_token_created_body'));
     }
@@ -99,7 +99,7 @@ class NewAccessToken extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/User/RuleActionFailed.php b/app/Notifications/User/RuleActionFailed.php
index b9f3ed9f05..9a518edb2e 100644
--- a/app/Notifications/User/RuleActionFailed.php
+++ b/app/Notifications/User/RuleActionFailed.php
@@ -59,7 +59,7 @@ class RuleActionFailed extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -86,7 +86,7 @@ class RuleActionFailed extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $groupTitle = $this->groupTitle;
         $groupLink  = $this->groupLink;
@@ -103,7 +103,7 @@ class RuleActionFailed extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         $channels = ReturnsAvailableChannels::returnChannels('user', $notifiable);
         if (($key = array_search('mail', $channels, true)) !== false) {
diff --git a/app/Notifications/User/TransactionCreation.php b/app/Notifications/User/TransactionCreation.php
index 82a5606e86..bca7218b62 100644
--- a/app/Notifications/User/TransactionCreation.php
+++ b/app/Notifications/User/TransactionCreation.php
@@ -46,7 +46,7 @@ class TransactionCreation extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -55,7 +55,7 @@ class TransactionCreation extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         return (new MailMessage())
             ->markdown('emails.report-new-journals', ['transformed' => $this->collection])
@@ -66,7 +66,7 @@ class TransactionCreation extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ['mail'];
     }
diff --git a/app/Notifications/User/UserLogin.php b/app/Notifications/User/UserLogin.php
index 3cadefb41c..c142c1ea69 100644
--- a/app/Notifications/User/UserLogin.php
+++ b/app/Notifications/User/UserLogin.php
@@ -43,7 +43,7 @@ class UserLogin extends Notification
 {
     use Queueable;
 
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -52,7 +52,7 @@ class UserLogin extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $ip        = Request::ip();
         $host      = Steam::getHostName($ip);
@@ -94,7 +94,7 @@ class UserLogin extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         $ip   = Request::ip();
         $host = Steam::getHostName($ip);
@@ -105,7 +105,7 @@ class UserLogin extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Notifications/User/UserNewPassword.php b/app/Notifications/User/UserNewPassword.php
index 372e8c0df3..d69e4abd8e 100644
--- a/app/Notifications/User/UserNewPassword.php
+++ b/app/Notifications/User/UserNewPassword.php
@@ -53,7 +53,7 @@ class UserNewPassword extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toArray(User $notifiable)
+    public function toArray(User $notifiable): array
     {
         return [
         ];
@@ -62,7 +62,7 @@ class UserNewPassword extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toMail(User $notifiable)
+    public function toMail(User $notifiable): MailMessage
     {
         $ip        = Request::ip();
         $host      = Steam::getHostName($ip);
@@ -96,12 +96,12 @@ class UserNewPassword extends Notification
     /**
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function toSlack(User $notifiable)
+    public function toSlack(User $notifiable): SlackMessage
     {
         return new SlackMessage()->content((string) trans('email.reset_pw_message'));
     }
 
-    public function via(User $notifiable)
+    public function via(User $notifiable): array
     {
         return ReturnsAvailableChannels::returnChannels('user', $notifiable);
     }
diff --git a/app/Support/Models/BillDateCalculator.php b/app/Support/Models/BillDateCalculator.php
index 038f2b0364..f8b5e9f376 100644
--- a/app/Support/Models/BillDateCalculator.php
+++ b/app/Support/Models/BillDateCalculator.php
@@ -117,7 +117,7 @@ class BillDateCalculator
             }
         }
         Log::debug('end of loop');
-        $simple             = $set->map(
+        $simple             = $set->map( // @phpstan-ignore-line
             static function (Carbon $date) {
                 return $date->format('Y-m-d');
             }
diff --git a/app/Support/Preferences.php b/app/Support/Preferences.php
index d627b00afd..2e5b10ef9d 100644
--- a/app/Support/Preferences.php
+++ b/app/Support/Preferences.php
@@ -195,7 +195,7 @@ class Preferences
         return $result;
     }
 
-    public function getEncrypted(string $name, $default = null): ?Preference
+    public function getEncrypted(string $name, mixed $default = null): ?Preference
     {
         $result = $this->get($name, $default);
         if (null === $result) {
diff --git a/app/Transformers/V2/BillTransformer.php b/app/Transformers/V2/BillTransformer.php
index e52d17d38d..04041785f6 100644
--- a/app/Transformers/V2/BillTransformer.php
+++ b/app/Transformers/V2/BillTransformer.php
@@ -326,7 +326,7 @@ class BillTransformer extends AbstractTransformer
                 break;
             }
         }
-        $simple       = $set->map(
+        $simple       = $set->map( // @phpstan-ignore-line
             static function (Carbon $date) {
                 return $date->toAtomString();
             }
diff --git a/app/User.php b/app/User.php
index 60dccbce9b..51d27e3b6f 100644
--- a/app/User.php
+++ b/app/User.php
@@ -400,7 +400,7 @@ class User extends Authenticatable
         return $this->belongsToMany(Role::class);
     }
 
-    public function routeNotificationForPushover()
+    public function routeNotificationForPushover(): PushoverReceiver
     {
         $appToken  = (string) app('preferences')->getEncrypted('pushover_app_token', '')->data;
         $userToken = (string) app('preferences')->getEncrypted('pushover_user_token', '')->data;
diff --git a/app/Validation/FireflyValidator.php b/app/Validation/FireflyValidator.php
index ffe70c6ea4..2dc360a134 100644
--- a/app/Validation/FireflyValidator.php
+++ b/app/Validation/FireflyValidator.php
@@ -100,12 +100,9 @@ class FireflyValidator extends Validator
     }
 
     /**
-     * @param mixed $attribute
-     * @param mixed $value
-     *
      * @SuppressWarnings("PHPMD.UnusedFormalParameter")
      */
-    public function validateBic($attribute, $value): bool
+    public function validateBic(mixed $attribute,mixed  $value): bool
     {
         $regex  = '/^[a-z]{6}[0-9a-z]{2}([0-9a-z]{3})?\z/i';
         $result = preg_match($regex, $value);
@@ -116,7 +113,7 @@ class FireflyValidator extends Validator
         return true;
     }
 
-    public function validateExistingMfaCode($attribute, $value): bool
+    public function validateExistingMfaCode(mixed $attribute, mixed $value): bool
     {
         if (!is_string($value) || 6 !== strlen($value)) {
             return false;