diff --git a/mail_safety.api.php b/mail_safety.api.php
index 8cbc29a..a192e9a 100644
--- a/mail_safety.api.php
+++ b/mail_safety.api.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file
  * Hooks provided by the Mail Safety module.
@@ -13,7 +14,7 @@
  * @return array
  *   Return the message array after any changes.
  */
-function hook_mail_safety_pre_insert($message) {
+function hook_mail_safety_pre_insert(array $message) {
   // Check to see if there are attachments.
   if (!empty($message['params']['attachments'])) {
     // Loop through the attachments and save the files.
@@ -36,7 +37,7 @@ function hook_mail_safety_pre_insert($message) {
  * @return array
  *   Return the message array after any changes.
  */
-function hook_mail_safety_load($message) {
+function hook_mail_safety_load(array $message) {
   if (!empty($message['attachments'])) {
     $message['has_attachments'] = TRUE;
   }
@@ -52,15 +53,15 @@ function hook_mail_safety_load($message) {
  * @return array
  *   Return the message array after any changes.
  */
-function hook_mail_safety_pre_send($message) {
+function hook_mail_safety_pre_send(array $message) {
   // Loop through the attachments in a message.
   foreach ($message['attachments'] as $key => $attachment) {
     // Return the attachment to the e-mail to send it again.
-    $message['params']['attachments'][$key] = array(
+    $message['params']['attachments'][$key] = [
       'content' => file_get_contents($attachment->uri),
       'mime' => $attachment->filemime,
       'filename' => $attachment->filename,
-    );
+    ];
   }
   return $message;
 }
@@ -71,23 +72,23 @@ function hook_mail_safety_pre_send($message) {
  * @param array $table_structure
  *   The table structure that will be rendered as table.
  */
-function hook_mail_safety_table_structure_alter($table_structure) {
+function hook_mail_safety_table_structure_alter(array $table_structure) {
   // Add a new column.
-  $table_structure['header'][] = array(
+  $table_structure['header'][] = [
     'data' => t('Files'),
-  );
+  ];
 
   // Loop through the mails to add the attachments in the table.
   foreach ($table_structure['rows'] as $mail_id => $row) {
     $mail = mail_safety_load($mail_id);
 
     if (!empty($mail['mail']['attachments'])) {
-      $attachments = array();
+      $attachments = [];
       foreach ($mail['mail']['attachments'] as $attachment) {
-        $attachments[] = array(
+        $attachments[] = [
           '#theme' => 'file_link',
           '#file' => $attachment,
-        );
+        ];
       }
     }
     $table_structure['rows'][$mail_id]['data'][] = $attachments;
diff --git a/mail_safety.module b/mail_safety.module
index 5b2dba5..6fbd41e 100644
--- a/mail_safety.module
+++ b/mail_safety.module
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file
  * The core Mail Safety module file.
@@ -11,12 +12,12 @@ use Drupal\mail_safety\Controller\MailSafetyController;
  */
 function mail_safety_theme() {
   return [
-    'mail_safety_mail' => array(
-      'variables' => array('mail' => NULL),
-    ),
-    'mail_safety_details' => array(
-      'variables' => array('mail' => NULL, 'details' => NULL),
-    ),
+    'mail_safety_mail' => [
+      'variables' => ['mail' => NULL],
+    ],
+    'mail_safety_details' => [
+      'variables' => ['mail' => NULL, 'details' => NULL],
+    ],
   ];
 }
 
@@ -36,7 +37,7 @@ function mail_safety_mail_alter(&$message) {
   }
   // If mail to dashboard is enabled it'll send the mail to the dashboard.
   if ($config->get('send_mail_to_dashboard')) {
-    \Drupal\mail_safety\Controller\MailSafetyController::insert($message);
+    MailSafetyController::insert($message);
   }
 
   // If mail to default mail is enabled it will send the mail to the default
diff --git a/src/Controller/MailSafetyController.php b/src/Controller/MailSafetyController.php
index 7defba1..4b632bd 100644
--- a/src/Controller/MailSafetyController.php
+++ b/src/Controller/MailSafetyController.php
@@ -1,12 +1,14 @@
 <?php
+
 namespace Drupal\mail_safety\Controller;
 
 /**
- * Class MailSafetyController
+ * Class MailSafetyController.
+ *
  * @package Drupal\mail_safety\Controller
  */
 class MailSafetyController {
-  
+
   /**
    * Let's the user view the e-mail caught by Mail Safety.
    *
@@ -22,7 +24,7 @@ class MailSafetyController {
       '#mail' => $mail_safety['mail'],
     ];
   }
-  
+
   /**
    * Let's the user view the details of an e-mail caught by Mail Safety.
    *
@@ -40,7 +42,7 @@ class MailSafetyController {
   /**
    * Load one or more mails.
    *
-   * @param (optional) $mail_id
+   * @param string $mail_id
    *   If mail_id is not given it will load all the mails.
    *
    * @return array|bool
@@ -51,7 +53,7 @@ class MailSafetyController {
 
     $connection = \Drupal::database();
     $query = $connection->select('mail_safety_dashboard', 'msd');
-    $query->fields('msd', array('mail_id', 'sent', 'mail'));
+    $query->fields('msd', ['mail_id', 'sent', 'mail']);
 
     // Add a condition for the mail id is given.
     if (!is_null($mail_id)) {
@@ -63,11 +65,11 @@ class MailSafetyController {
     $result = $query->execute();
 
     while ($row = $result->fetchAssoc()) {
-      $mails[$row['mail_id']] = array(
+      $mails[$row['mail_id']] = [
         'mail' => unserialize($row['mail']),
         'sent' => $row['sent'],
         'mail_id' => $row['mail_id'],
-      );
+      ];
     };
 
     // Let other modules respond before a mail is loaded.
@@ -96,6 +98,7 @@ class MailSafetyController {
    * Delete a mail from the database.
    *
    * @param int $mail_id
+   *   The mail id.
    */
   public static function delete($mail_id) {
     $connection = \Drupal::database();
@@ -110,15 +113,15 @@ class MailSafetyController {
    * @param array $message
    *   The drupal message array.
    */
-  public static function insert($message) {
+  public static function insert(array $message) {
     // Let other modules alter the message array before a mail is inserted.
     // E.g. save attachments that are sent with the mail.
     \Drupal::moduleHandler()->alter('mail_safety_pre_insert', $message);
 
-    $mail = array(
+    $mail = [
       'sent' => time(),
       'mail' => serialize($message),
-    );
+    ];
 
     $connection = \Drupal::database();
     $connection->insert('mail_safety_dashboard')
@@ -135,10 +138,9 @@ class MailSafetyController {
    * @return object
    *   The mail system object.
    */
-  public static function getMailSystem($mail) {
+  public static function getMailSystem(array $mail) {
     $mail_manager = \Drupal::service('plugin.manager.mail');
-    return $mail_manager->getInstance(array('module' => $mail['module'], 'key' => $mail['key']));
+    return $mail_manager->getInstance(['module' => $mail['module'], 'key' => $mail['key']]);
   }
 
 }
-
diff --git a/src/Form/DashboardForm.php b/src/Form/DashboardForm.php
index d55f14f..77c13ab 100644
--- a/src/Form/DashboardForm.php
+++ b/src/Form/DashboardForm.php
@@ -1,4 +1,5 @@
 <?php
+
 namespace Drupal\mail_safety\Form;
 
 use Drupal\Core\Form\FormBase;
@@ -25,20 +26,20 @@ class DashboardForm extends FormBase {
    * {@inheritdoc}
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
-    $table_structure = array();
+    $table_structure = [];
     // Create the headers.
-    $table_structure['header'] = array(
-      array('data' => t('Subject')),
-      array('data' => t('Date sent'), 'field' => 'sent', 'sort' => 'desc'),
-      array('data' => t('To')),
-      array('data' => t('CC')),
-      array('data' => t('Module')),
-      array('data' => t('Key')),
-      array('data' => t('Details')),
-      array('data' => t('Send to original')),
-      array('data' => t('Send to default mail')),
-      array('data' => t('Delete')),
-    );
+    $table_structure['header'] = [
+      ['data' => t('Subject')],
+      ['data' => t('Date sent'), 'field' => 'sent', 'sort' => 'desc'],
+      ['data' => t('To')],
+      ['data' => t('CC')],
+      ['data' => t('Module')],
+      ['data' => t('Key')],
+      ['data' => t('Details')],
+      ['data' => t('Send to original')],
+      ['data' => t('Send to default mail')],
+      ['data' => t('Delete')],
+    ];
 
     $connection = \Drupal::database();
     // Create the query.
@@ -47,11 +48,11 @@ class DashboardForm extends FormBase {
       ->limit(50)
       ->extend('Drupal\Core\Database\Query\TableSortExtender')
       ->orderByHeader($table_structure['header'])
-      ->fields('msd', array(
+      ->fields('msd', [
         'mail_id',
         'sent',
         'mail',
-      ));
+      ]);
 
     $results = $query->execute();
 
@@ -62,14 +63,14 @@ class DashboardForm extends FormBase {
       $mail = unserialize($row->mail);
 
       // Build the links for the row.
-      $view_url = Url::fromRoute('mail_safety.view', array('mail_safety' => $row->mail_id));
-      $details_url = Url::fromRoute('mail_safety.details', array('mail_safety' => $row->mail_id));
-      $send_original_url = Url::fromRoute('mail_safety.send_original', array('mail_safety' => $row->mail_id));
-      $send_default_url = Url::fromRoute('mail_safety.send_default', array('mail_safety' => $row->mail_id));
-      $delete_url = Url::fromRoute('mail_safety.delete', array('mail_safety' => $row->mail_id));
-
-      $table_structure['rows'][$row->mail_id] = array(
-        'data' => array(
+      $view_url = Url::fromRoute('mail_safety.view', ['mail_safety' => $row->mail_id]);
+      $details_url = Url::fromRoute('mail_safety.details', ['mail_safety' => $row->mail_id]);
+      $send_original_url = Url::fromRoute('mail_safety.send_original', ['mail_safety' => $row->mail_id]);
+      $send_default_url = Url::fromRoute('mail_safety.send_default', ['mail_safety' => $row->mail_id]);
+      $delete_url = Url::fromRoute('mail_safety.delete', ['mail_safety' => $row->mail_id]);
+
+      $table_structure['rows'][$row->mail_id] = [
+        'data' => [
           Link::fromTextAndUrl($mail['subject'], $view_url),
           \Drupal::service('date.formatter')->format((int) $row->sent, 'short'),
           $mail['to'],
@@ -80,27 +81,28 @@ class DashboardForm extends FormBase {
           Link::fromTextAndUrl($this->t('Send to original'), $send_original_url),
           Link::fromTextAndUrl($this->t('Send to default mail'), $send_default_url),
           Link::fromTextAndUrl($this->t('Delete'), $delete_url),
-        ),
-      );
+        ],
+      ];
     }
 
     // Let other modules change the table structure to add or remove
     // information to be shown. E.g. attachments that need to be downloaded.
-    \Drupal::moduleHandler()->alter('mail_safety_table_structure', $table_structure);
+    \Drupal::moduleHandler()
+      ->alter('mail_safety_table_structure', $table_structure);
 
-    $form['mails']['table'] = array(
+    $form['mails']['table'] = [
       '#theme' => 'table',
       '#header' => $table_structure['header'],
       '#rows' => $table_structure['rows'],
       '#caption' => 'Mail Safety Dashboard',
       '#sticky' => TRUE,
       '#empty' => t('No mails found'),
-    );
+    ];
 
-    $form['mails']['pager'] = array(
+    $form['mails']['pager'] = [
       '#type' => 'pager',
-      '#tags' => array(),
-    );
+      '#tags' => [],
+    ];
 
     return $form;
   }
diff --git a/src/Form/DeleteForm.php b/src/Form/DeleteForm.php
index 278d0bc..9f6d118 100644
--- a/src/Form/DeleteForm.php
+++ b/src/Form/DeleteForm.php
@@ -1,8 +1,9 @@
 <?php
+
 namespace Drupal\mail_safety\Form;
 
-use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Form\ConfirmFormBase;
+use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Url;
 use Drupal\mail_safety\Controller\MailSafetyController;
 
diff --git a/src/Form/SendDefaultForm.php b/src/Form/SendDefaultForm.php
index 1ee71c6..1391554 100644
--- a/src/Form/SendDefaultForm.php
+++ b/src/Form/SendDefaultForm.php
@@ -1,8 +1,9 @@
 <?php
+
 namespace Drupal\mail_safety\Form;
 
-use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Form\ConfirmFormBase;
+use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Url;
 use Drupal\mail_safety\Controller\MailSafetyController;
 
@@ -33,7 +34,10 @@ class SendDefaultForm extends ConfirmFormBase {
   public function getQuestion() {
     $config = \Drupal::config('mail_safety.settings');
 
-    return $this->t('Are you sure you want to send "@subject" to @to', array('@subject' => $this->mailSafety['mail']['subject'], '@to' => $config->get('default_mail_address')));
+    return $this->t('Are you sure you want to send "@subject" to @to', [
+      '@subject' => $this->mailSafety['mail']['subject'],
+      '@to' => $config->get('default_mail_address'),
+    ]);
   }
 
   /**
@@ -57,12 +61,12 @@ class SendDefaultForm extends ConfirmFormBase {
     $config = \Drupal::config('mail_safety.settings');
     $this->mailSafety = $mail_safety;
 
-    $form['to'] = array(
+    $form['to'] = [
       '#type' => 'textfield',
       '#title' => t('Send to another address'),
       '#description' => t('Only use this field if you want the e-mail to go to an address other than the default address.'),
       '#default_value' => $config->get('default_mail_address'),
-    );
+    ];
 
     return parent::buildForm($form, $form_state);
   }
@@ -93,10 +97,12 @@ class SendDefaultForm extends ConfirmFormBase {
     $mail_array['result'] = $system->mail($mail_array);
 
     if ($mail_array['result']) {
-      drupal_set_message(t('Succesfully sent the message to @to', array('@to' => $mail_array['to'])));
+      $this->messenger()
+        ->addMessage($this->t('Succesfully sent the message to @to', ['@to' => $mail_array['to']]));
     }
     else {
-      drupal_set_message(t('Failed to send the message to @to', array('@to' => $mail_array['to'])), 'error');
+      $this->messenger()
+        ->addError($this->t('Failed to send the message to @to', ['@to' => $mail_array['to']]));
     }
     $form_state->setRedirectUrl($this->getCancelUrl());
   }
diff --git a/src/Form/SendOriginalForm.php b/src/Form/SendOriginalForm.php
index f55c25d..2cd6a9b 100644
--- a/src/Form/SendOriginalForm.php
+++ b/src/Form/SendOriginalForm.php
@@ -1,8 +1,9 @@
 <?php
+
 namespace Drupal\mail_safety\Form;
 
-use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Form\ConfirmFormBase;
+use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Url;
 use Drupal\mail_safety\Controller\MailSafetyController;
 
@@ -19,6 +20,7 @@ class SendOriginalForm extends ConfirmFormBase {
    * @var array
    */
   protected $mailSafety = [];
+
   /**
    * {@inheritdoc}
    */
@@ -30,7 +32,10 @@ class SendOriginalForm extends ConfirmFormBase {
    * {@inheritdoc}
    */
   public function getQuestion() {
-    return $this->t('Are you sure you want to send "@subject" to @to', array('@subject' => $this->mailSafety['mail']['subject'], '@to' => $this->mailSafety['mail']['to']));
+    return $this->t('Are you sure you want to send "@subject" to @to', [
+      '@subject' => $this->mailSafety['mail']['subject'],
+      '@to' => $this->mailSafety['mail']['to'],
+    ]);
   }
 
   /**
@@ -80,10 +85,10 @@ class SendOriginalForm extends ConfirmFormBase {
     $mail_array['result'] = $system->mail($mail_array);
 
     if ($mail_array['result']) {
-      drupal_set_message(t('Succesfully sent the message to @to', array('@to' => $mail_array['to'])));
+      $this->messenger()->addMessage($this->t('Succesfully sent the message to @to', ['@to' => $mail_array['to']]));
     }
     else {
-      drupal_set_message(t('Failed to send the message to @to', array('@to' => $mail_array['to'])), 'error');
+      $this->messenger()->addError($this->t('Failed to send the message to @to', ['@to' => $mail_array['to']]));
     }
     $form_state->setRedirectUrl($this->getCancelUrl());
   }
diff --git a/src/Form/SettingsForm.php b/src/Form/SettingsForm.php
index 5ade236..7bac917 100644
--- a/src/Form/SettingsForm.php
+++ b/src/Form/SettingsForm.php
@@ -1,4 +1,5 @@
 <?php
+
 namespace Drupal\mail_safety\Form;
 
 use Drupal\Core\Form\ConfigFormBase;
@@ -8,6 +9,7 @@ use Drupal\Core\Form\FormStateInterface;
  * Defines a form for the mail safety settings.
  */
 class SettingsForm extends ConfigFormBase {
+
   /**
    * {@inheritdoc}
    */
@@ -27,34 +29,34 @@ class SettingsForm extends ConfigFormBase {
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
     $config = $this->config('mail_safety.settings');
-    
-    $form['enabled'] = array(
+
+    $form['enabled'] = [
       '#title' => t('Stop outgoing mails'),
       '#type' => 'checkbox',
       '#description' => t('When Mail Safety is enabled it will stop all outgoing emails from being sent and will send them to either the dashboard and/or the defaut mail address instead.'),
       '#default_value' => $config->get('enabled'),
-    );
+    ];
 
-    $form['send_mail_to_dashboard'] = array(
+    $form['send_mail_to_dashboard'] = [
       '#title' => t('Send mail to dashboard'),
       '#type' => 'checkbox',
       '#description' => t('If enabled, all mails will be sent to the dashboard'),
       '#default_value' => $config->get('send_mail_to_dashboard'),
-    );
+    ];
 
-    $form['send_mail_to_default_mail'] = array(
+    $form['send_mail_to_default_mail'] = [
       '#title' => t('Send mail to default mail'),
       '#type' => 'checkbox',
       '#description' => t('If enabled, all mails will be sent to the the default mail address'),
       '#default_value' => $config->get('send_mail_to_default_mail'),
-    );
+    ];
 
-    $form['default_mail_address'] = array(
+    $form['default_mail_address'] = [
       '#title' => t('Default mail address'),
       '#type' => 'textfield',
       '#description' => t('The default email address that outgoing e-mails will be rerouted to if enabled.'),
       '#default_value' => $config->get('default_mail_address'),
-    );
+    ];
 
     return parent::buildForm($form, $form_state);
   }
diff --git a/src/ParamConverter/MailSafetyParamConverter.php b/src/ParamConverter/MailSafetyParamConverter.php
index c7dbf51..0405cc8 100644
--- a/src/ParamConverter/MailSafetyParamConverter.php
+++ b/src/ParamConverter/MailSafetyParamConverter.php
@@ -1,4 +1,5 @@
 <?php
+
 namespace Drupal\mail_safety\ParamConverter;
 
 use Drupal\Core\ParamConverter\ParamConverterInterface;