diff --git a/Classes/Backend/PreviewRenderer/Video.php b/Classes/Backend/PreviewRenderer/Video.php
index 79158ea..60fdc1a 100644
--- a/Classes/Backend/PreviewRenderer/Video.php
+++ b/Classes/Backend/PreviewRenderer/Video.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace DanielSiepmann\DsSite\Backend\PreviewRenderer;
+declare(strict_types=1);
 
 /*
  * Copyright (C) 2020 Daniel Siepmann <coding@daniel-siepmann.de>
@@ -21,6 +21,8 @@ namespace DanielSiepmann\DsSite\Backend\PreviewRenderer;
  * 02110-1301, USA.
  */
 
+namespace DanielSiepmann\DsSite\Backend\PreviewRenderer;
+
 use TYPO3\CMS\Backend\Preview\StandardContentPreviewRenderer;
 use TYPO3\CMS\Backend\View\BackendLayout\Grid\GridColumnItem;
 use TYPO3\CMS\Frontend\ContentObject\ContentDataProcessor;
diff --git a/Classes/EventListener/AddFurtherMetadataToFile.php b/Classes/EventListener/AddFurtherMetadataToFile.php
index a7f2307..849d325 100644
--- a/Classes/EventListener/AddFurtherMetadataToFile.php
+++ b/Classes/EventListener/AddFurtherMetadataToFile.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace DanielSiepmann\DsSite\EventListener;
+declare(strict_types=1);
 
 /*
  * Copyright (C) 2020 Daniel Siepmann <coding@daniel-siepmann.de>
@@ -21,6 +21,8 @@ namespace DanielSiepmann\DsSite\EventListener;
  * 02110-1301, USA.
  */
 
+namespace DanielSiepmann\DsSite\EventListener;
+
 use TYPO3\CMS\Core\Resource\Event\EnrichFileMetaDataEvent;
 use TYPO3\CMS\Core\Resource\FileReference;
 use TYPO3\CMS\Frontend\Resource\FileCollector;
diff --git a/Classes/Frontend/DataProcessing/CategoriesCounts.php b/Classes/Frontend/DataProcessing/CategoriesCounts.php
index dc1c4cb..41d178b 100644
--- a/Classes/Frontend/DataProcessing/CategoriesCounts.php
+++ b/Classes/Frontend/DataProcessing/CategoriesCounts.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace DanielSiepmann\DsSite\Frontend\DataProcessing;
+declare(strict_types=1);
 
 /*
  * Copyright (C) 2020 Daniel Siepmann <coding@daniel-siepmann.de>
@@ -21,6 +21,8 @@ namespace DanielSiepmann\DsSite\Frontend\DataProcessing;
  * 02110-1301, USA.
  */
 
+namespace DanielSiepmann\DsSite\Frontend\DataProcessing;
+
 use TYPO3\CMS\Core\Database\Query\QueryBuilder;
 use TYPO3\CMS\Core\Database\Query\QueryHelper;
 use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;
diff --git a/Classes/Frontend/RssFeed/SitemapDataProvider.php b/Classes/Frontend/RssFeed/SitemapDataProvider.php
index 0937df5..e6edd19 100644
--- a/Classes/Frontend/RssFeed/SitemapDataProvider.php
+++ b/Classes/Frontend/RssFeed/SitemapDataProvider.php
@@ -1,7 +1,6 @@
 <?php
 
-namespace DanielSiepmann\DsSite\Frontend\RssFeed;
-
+declare(strict_types=1);
 
 /*
  * Copyright (C) 2021 Daniel Siepmann <coding@daniel-siepmann.de>
@@ -22,6 +21,8 @@ namespace DanielSiepmann\DsSite\Frontend\RssFeed;
  * 02110-1301, USA.
  */
 
+namespace DanielSiepmann\DsSite\Frontend\RssFeed;
+
 use Psr\Http\Message\ServerRequestInterface;
 use TYPO3\CMS\Core\Database\Connection;
 use TYPO3\CMS\Core\Database\ConnectionPool;
diff --git a/Classes/Frontend/RssFeed/XmlSitemapRenderer.php b/Classes/Frontend/RssFeed/XmlSitemapRenderer.php
index 9c96d09..2065b68 100644
--- a/Classes/Frontend/RssFeed/XmlSitemapRenderer.php
+++ b/Classes/Frontend/RssFeed/XmlSitemapRenderer.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace DanielSiepmann\DsSite\Frontend\RssFeed;
+declare(strict_types=1);
 
 /*
  * Copyright (C) 2021 Daniel Siepmann <coding@daniel-siepmann.de>
@@ -21,6 +21,8 @@ namespace DanielSiepmann\DsSite\Frontend\RssFeed;
  * 02110-1301, USA.
  */
 
+namespace DanielSiepmann\DsSite\Frontend\RssFeed;
+
 use Psr\Http\Message\ServerRequestInterface;
 use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;
 use TYPO3\CMS\Seo\XmlSitemap\XmlSitemapRenderer as Typo3XmlSitemapRenderer;
diff --git a/Classes/Hooks/Backend/PageLayoutHeader.php b/Classes/Hooks/Backend/PageLayoutHeader.php
index c5cc2ae..b43f968 100644
--- a/Classes/Hooks/Backend/PageLayoutHeader.php
+++ b/Classes/Hooks/Backend/PageLayoutHeader.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace DanielSiepmann\DsSite\Hooks\Backend;
+declare(strict_types=1);
 
 /*
  * Copyright (C) 2019 Daniel Siepmann <coding@daniel-siepmann.de>
@@ -21,6 +21,8 @@ namespace DanielSiepmann\DsSite\Hooks\Backend;
  * 02110-1301, USA.
  */
 
+namespace DanielSiepmann\DsSite\Hooks\Backend;
+
 use TYPO3\CMS\Backend\Controller\PageLayoutController;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Fluid\View\StandaloneView;
diff --git a/Classes/UserFunction/CodeHighlighting.php b/Classes/UserFunction/CodeHighlighting.php
index ba38eea..1d4902c 100644
--- a/Classes/UserFunction/CodeHighlighting.php
+++ b/Classes/UserFunction/CodeHighlighting.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace DanielSiepmann\DsSite\UserFunction;
+declare(strict_types=1);
 
 /*
  * Copyright (C) 2019 Daniel Siepmann <coding@daniel-siepmann.de>
@@ -21,6 +21,8 @@ namespace DanielSiepmann\DsSite\UserFunction;
  * 02110-1301, USA.
  */
 
+namespace DanielSiepmann\DsSite\UserFunction;
+
 use Highlight\Highlighter;
 use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;