diff --git a/Admin/Install/Navigation.php b/Admin/Install/Navigation.php
index 6aaf8c9..4431e2d 100644
--- a/Admin/Install/Navigation.php
+++ b/Admin/Install/Navigation.php
@@ -38,7 +38,7 @@ class Navigation
      */
     public static function install(string $path = null, DatabasePool $dbPool = null) : void
     {
-        $navData = json_decode(file_get_contents(__DIR__ . '/Navigation.install.json'), true);
+        $navData = \json_decode(file_get_contents(__DIR__ . '/Navigation.install.json'), true);
 
         $class = '\\Modules\\Navigation\\Admin\\Installer';
         /** @var $class \Modules\Navigation\Admin\Installer */
diff --git a/Theme/Backend/dashboard.tpl.php b/Theme/Backend/dashboard.tpl.php
index af271f8..f49dd27 100644
--- a/Theme/Backend/dashboard.tpl.php
+++ b/Theme/Backend/dashboard.tpl.php
@@ -43,7 +43,7 @@ echo $this->getData('nav')->render(); ?>
             <tr>
                 <td><span class="check"><input type="checkbox"></span>
                 <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>></a>
-                <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
+                <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(\str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
                 <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml($value->from); ?></a>
                 <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml((new \DateTime($value->date))->format('Y-m-d H:i:s')); ?></a>
             <?php endforeach; ?>
@@ -53,7 +53,7 @@ echo $this->getData('nav')->render(); ?>
             <tr>
                 <td><span class="check"><input type="checkbox"></span>
                 <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>></a>
-                <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
+                <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(\str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
                 <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml($value->from); ?></a>
                 <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml((new \DateTime($value->date))->format('Y-m-d H:i:s')); ?></a>
                     <?php endforeach; ?>
diff --git a/Theme/Backend/mail-out-view.tpl.php b/Theme/Backend/mail-out-view.tpl.php
index c5231ef..a9a4e52 100644
--- a/Theme/Backend/mail-out-view.tpl.php
+++ b/Theme/Backend/mail-out-view.tpl.php
@@ -42,7 +42,7 @@ echo $this->getData('nav')->render(); ?>
         <tr>
             <td><span class="check"><input type="checkbox"></span>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>></a>
-            <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
+            <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(\str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml($value->from); ?></a>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml((new \DateTime($value->date))->format('Y-m-d H:i:s')); ?></a>
                 <?php endforeach; ?>
diff --git a/Theme/Backend/mail-spam-view.tpl.php b/Theme/Backend/mail-spam-view.tpl.php
index c5231ef..a9a4e52 100644
--- a/Theme/Backend/mail-spam-view.tpl.php
+++ b/Theme/Backend/mail-spam-view.tpl.php
@@ -42,7 +42,7 @@ echo $this->getData('nav')->render(); ?>
         <tr>
             <td><span class="check"><input type="checkbox"></span>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>></a>
-            <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
+            <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(\str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml($value->from); ?></a>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml((new \DateTime($value->date))->format('Y-m-d H:i:s')); ?></a>
                 <?php endforeach; ?>
diff --git a/Theme/Backend/mail-trash-view.tpl.php b/Theme/Backend/mail-trash-view.tpl.php
index c5231ef..a9a4e52 100644
--- a/Theme/Backend/mail-trash-view.tpl.php
+++ b/Theme/Backend/mail-trash-view.tpl.php
@@ -42,7 +42,7 @@ echo $this->getData('nav')->render(); ?>
         <tr>
             <td><span class="check"><input type="checkbox"></span>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>></a>
-            <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
+            <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml(\str_replace('_',' ', mb_decode_mimeheader($value->subject))); ?></a>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml($value->from); ?></a>
             <td><a href="<?= $url; ?>"<?= $this->printHtml($value->seen == 0 ? ' class="unseen"' : ''); ?>><?= $this->printHtml((new \DateTime($value->date))->format('Y-m-d H:i:s')); ?></a>
                 <?php endforeach; ?>
diff --git a/Theme/Backend/mail-view.tpl.php b/Theme/Backend/mail-view.tpl.php
index ee2ca26..73ce77c 100644
--- a/Theme/Backend/mail-view.tpl.php
+++ b/Theme/Backend/mail-view.tpl.php
@@ -17,7 +17,7 @@ $mails = $mail->getEmail($this->getData('id'));
 echo $this->getData('nav')->render(); ?>
 
 <section class="box w-100">
-    <header><h1><?= $this->printHtml(str_replace('_',' ', mb_decode_mimeheader($mails['overview'][0]->subject))); ?></h1></header>
+    <header><h1><?= $this->printHtml(\str_replace('_',' ', mb_decode_mimeheader($mails['overview'][0]->subject))); ?></h1></header>
     <div class="inner">
         <?= $this->printHtml($mail::decode($mails['body'], $mails['encoding']->encoding)); ?>
     </div>