diff --git a/src/Form/TourBuilderCloneForm.php b/src/Form/TourBuilderCloneForm.php
index 4fb22b3..2ff664b 100644
--- a/src/Form/TourBuilderCloneForm.php
+++ b/src/Form/TourBuilderCloneForm.php
@@ -6,12 +6,15 @@ use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Entity\EntityForm;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Form controller for the tour entity clone form.
  */
 class TourBuilderCloneForm extends EntityForm {
 
+  use StringTranslationTrait;
+
   /**
    * Entity manager service.
    *
@@ -33,10 +36,6 @@ class TourBuilderCloneForm extends EntityForm {
    *
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
    *   The entity manager service.
-   * @param \Psr\Log\LoggerInterface $logger
-   *   A logger instance.
-   * @param \Drupal\comment\CommentManagerInterface $comment_manager
-   *   The comment manager.
    */
   public function __construct(EntityTypeManagerInterface $entity_type_manager) {
     $this->entityTypeManager = $entity_type_manager;
@@ -55,24 +54,24 @@ class TourBuilderCloneForm extends EntityForm {
       '#default_value' => $this->entity->label(),
     ];
 
-    $form['old_name'] = array(
+    $form['old_name'] = [
       '#type' => 'value',
       '#value' => $this->entity->getOriginalId(),
-    );
+    ];
 
-    $form['new_name'] = array(
+    $form['new_name'] = [
       '#title' => 'File name for new tour item.',
       '#type' => 'textfield',
-      '#description' => 'This value should start with <strong>tour.tour.</strong> and may not exists.',
+      '#description' => $this->t('This value should start with <strong>tour.tour.</strong> and may not exists.'),
       '#field_prefix' => 'tour.tour.',
       '#default_value' => $this->entity->getOriginalId(),
-    );
+    ];
 
-    $form['module'] = array(
+    $form['module'] = [
       '#title' => 'Module for this tour.',
       '#type' => 'textfield',
       '#default_value' => $this->entity->getModule(),
-    );
+    ];
 
     return $form;
   }
@@ -82,7 +81,7 @@ class TourBuilderCloneForm extends EntityForm {
    */
   public function validateForm(array &$form, FormStateInterface $form_state, $redirect = TRUE) {
     // Make sure new_name does not exists
-    // Make sure module exists
+    // Make sure module exists.
     $old_name = $form_state->getValue('old_name');
     $new_name = $form_state->getValue('new_name');
 
@@ -99,11 +98,11 @@ class TourBuilderCloneForm extends EntityForm {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state, $redirect = TRUE) {
-    // No need to submit the form as we did nothing to the original entity did we?!
-    // parent::submitForm($form, $form_state);
-
+    // No need to submit the form as we did nothing to the original
+    // entity did we?!
+    // parent::submitForm($form, $form_state);.
     $this->entity = $this->entity->createDuplicate();
-    //$this->entity->set('label', $form_state->getValue('label'));
+    // $this->entity->set('label', $form_state->getValue('label'));
     $this->entity->set('id', $form_state->getValue('new_name'));
     $this->entity->save();
 
diff --git a/src/Form/TourBuilderExportForm.php b/src/Form/TourBuilderExportForm.php
index 6bb7c86..eff1baa 100644
--- a/src/Form/TourBuilderExportForm.php
+++ b/src/Form/TourBuilderExportForm.php
@@ -4,17 +4,19 @@ namespace Drupal\tour_builder\Form;
 
 use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\Url;
 use Drupal\Core\Entity\EntityForm;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\Core\Serialization\Yaml;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Form controller for the tour entity clone form.
  */
 class TourBuilderExportForm extends EntityForm {
 
+  use StringTranslationTrait;
+
   /**
    * Entity manager service.
    *
@@ -44,10 +46,8 @@ class TourBuilderExportForm extends EntityForm {
    *
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
    *   The entity manager service.
-   * @param \Psr\Log\LoggerInterface $logger
-   *   A logger instance.
-   * @param \Drupal\comment\CommentManagerInterface $comment_manager
-   *   The comment manager.
+   * @param \Drupal\Core\Config\StorageInterface $config_storage
+   *   The config storage service.
    */
   public function __construct(EntityTypeManagerInterface $entity_type_manager, StorageInterface $config_storage) {
     $this->entityTypeManager = $entity_type_manager;
@@ -60,8 +60,6 @@ class TourBuilderExportForm extends EntityForm {
   public function form(array $form, FormStateInterface $form_state) {
     $form = parent::form($form, $form_state);
 
-    $tour = $this->entity;
-
     $definition = $this->entityManager->getDefinition('tour');
     $name = $definition->getConfigPrefix() . '.' . $this->entity->getOriginalId();
 
@@ -70,22 +68,11 @@ class TourBuilderExportForm extends EntityForm {
       'uuid',
       '_core',
     ];
-    foreach($unset_keys as $key) {
+    foreach ($unset_keys as $key) {
       unset($config[$key]);
     }
     $content = Yaml::encode($config);
 
-//    $filename = $name . '.yml';
-//    $path = 'temporary://' . $filename;
-//    //$link = \Drupal::l($name, Url::fromUri($path));
-//    file_put_contents($path, $content);
-
-//    $form['link'] = array(
-//      '#type' => 'item',
-//      '#title' => $this->t('Download'),
-//      '#description' => 'Right click to download.',
-//      '#markup' => $link,
-//    );
     $form['export'] = [
       '#type' => 'textarea',
       '#title' => $this->t('YAML Content'),
@@ -101,8 +88,8 @@ class TourBuilderExportForm extends EntityForm {
    * {@inheritdoc}
    */
   public function validateForm(array &$form, FormStateInterface $form_state, $redirect = TRUE) {
-    // Make sure new_name does not exists
-    // Make sure module exists
+    // Make sure new_name does not exists.
+    // Make sure module exists.
     $old_name = $form_state->getValue('old_name');
     $new_name = $form_state->getValue('new_name');
 
@@ -119,9 +106,9 @@ class TourBuilderExportForm extends EntityForm {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state, $redirect = TRUE) {
-    // No need to submit the form as we did nothing to the original entity did we?!
-    // parent::submitForm($form, $form_state);
-
+    // No need to submit the form as we did nothing to the original
+    // entity did we?!
+    // parent::submitForm($form, $form_state);.
     // Redirect to Entity edition.
     if ($redirect) {
       $form_state->setRedirect('entity.tour.edit_form', ['tour' => $this->entity->id()]);
diff --git a/src/TourBuilderListBuilder.php b/src/TourBuilderListBuilder.php
index 07fb0b9..d482379 100644
--- a/src/TourBuilderListBuilder.php
+++ b/src/TourBuilderListBuilder.php
@@ -4,30 +4,17 @@ namespace Drupal\tour_builder;
 
 use Drupal\Core\Url;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Drupal\Core\Config\Entity\ConfigEntityStorageInterface;
-
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityTypeInterface;
-use Drupal\Component\Utility\Html;
-
 use Drupal\tour_ui\TourListBuilder;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
  * Provides a listing of tours.
  */
 class TourBuilderListBuilder extends TourListBuilder {
 
-  /**
-   * Constructs a new TourListBuilder object.
-   *
-   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
-   *   The entity type definition.
-   * @param \Drupal\Core\Config\Entity\ConfigEntityStorageInterface $storage
-   *   The config storage class.
-   */
-  public function __construct(EntityTypeInterface $entity_type, ConfigEntityStorageInterface $storage) {
-    parent::__construct($entity_type, $storage);
-  }
+  use StringTranslationTrait;
 
   /**
    * {@inheritdoc}
@@ -48,13 +35,13 @@ class TourBuilderListBuilder extends TourListBuilder {
     $tour = $entity->getOriginalId();
 
     $operations['clone'] = [
-      'title' => t('Clone'),
+      'title' => $this->t('Clone'),
       'url' => $entity->toUrl('clone-form'),
       'weight' => 11,
     ];
 
     $operations['export'] = [
-      'title' => t('Export'),
+      'title' => $this->t('Export'),
       'url' => $entity->toUrl('export-form'),
       'weight' => 12,
     ];
@@ -63,22 +50,15 @@ class TourBuilderListBuilder extends TourListBuilder {
 
     if ($user->hasPermission('export configuration')) {
       $operations['export-config'] = [
-        'title' => t('Export (configuration)'),
+        'title' => $this->t('Export (configuration)'),
         'url' => Url::fromRoute('config.export_single', [
           'config_type' => 'tour',
-          'config_name' => $tour
+          'config_name' => $tour,
         ]),
         'weight' => 13,
       ];
     }
 
-    // TODO: fix me
-//    $operations['patch'] = [
-//      'title' => t('Patch'),
-//      'url' => $entity->toUrl('edit-form'),
-//      'weight' => 11,
-//    ];
-
     return $operations;
   }
 
diff --git a/tour_builder.info.yml b/tour_builder.info.yml
index c2db998..3de7a0b 100644
--- a/tour_builder.info.yml
+++ b/tour_builder.info.yml
@@ -2,7 +2,7 @@ name: 'Tour Builder'
 type: module
 description: 'Helps building and editing tours.'
 package: Development
-
 core: 8.x
+core_version_requirement: ^8 || ^9
 dependencies:
   - tour_ui:tour_ui
diff --git a/tour_builder.install b/tour_builder.install
index 8e6a133..bef013e 100644
--- a/tour_builder.install
+++ b/tour_builder.install
@@ -1,8 +1,14 @@
 <?php
 
+/**
+ * @file
+ * Install, update and uninstall functions for the Tour Builder module.
+ */
+
+/**
+ * Implements hook_install().
+ */
 function tour_builder_install() {
-  // Set higher then tour_ui or tour module
+  // Set higher then tour_ui or tour module.
   module_set_weight('tour_builder', 1);
-  // TODO: this does not work
-  //Drupal::cache()->invalidateAll();
 }
diff --git a/tour_builder.module b/tour_builder.module
index 8558ee6..b1e35c7 100644
--- a/tour_builder.module
+++ b/tour_builder.module
@@ -5,8 +5,6 @@
  * Core functionality for Tour UI module.
  */
 
-use Drupal\Core\Entity\EntityInterface;
-
 /**
  * Implements hook_entity_type_alter().
  */