diff --git a/Admin/Routes/Web/Backend.php b/Admin/Routes/Web/Backend.php
index ac2c13f..129ec62 100644
--- a/Admin/Routes/Web/Backend.php
+++ b/Admin/Routes/Web/Backend.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Modules\BudgetManagement\Controller\BackendController;
 use Modules\BudgetManagement\Models\PermissionState;
diff --git a/Theme/Backend/Lang/Navigation.en.lang.php b/Theme/Backend/Lang/Navigation.en.lang.php
index 08457a8..8246d49 100644
--- a/Theme/Backend/Lang/Navigation.en.lang.php
+++ b/Theme/Backend/Lang/Navigation.en.lang.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Orange Management
  *
diff --git a/Theme/Backend/Lang/en.lang.php b/Theme/Backend/Lang/en.lang.php
index 2a786a7..7423d83 100644
--- a/Theme/Backend/Lang/en.lang.php
+++ b/Theme/Backend/Lang/en.lang.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Orange Management
  *
diff --git a/Theme/Backend/budgeting-dashboard.tpl.php b/Theme/Backend/budgeting-dashboard.tpl.php
index 559f971..0bb3664 100644
--- a/Theme/Backend/budgeting-dashboard.tpl.php
+++ b/Theme/Backend/budgeting-dashboard.tpl.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Orange Management
  *