diff --git a/course.devel.inc b/course.devel.inc
index 977be94..067f7bc 100644
--- a/course.devel.inc
+++ b/course.devel.inc
@@ -67,8 +67,8 @@ function course_generate_form($form, $form_state) {
  * Submit callback for devel_generate support.
  */
 function course_generate_form_submit($form, &$form_state) {
-  module_load_include('inc', 'devel_generate', 'devel_generate.fields');
-  module_load_include('inc', 'devel_generate', 'devel_generate');
+  \Drupal::moduleHandler()->loadInclude('devel_generate', 'inc', 'devel_generate.fields');
+  \Drupal::moduleHandler()->loadInclude('devel_generate', 'inc', 'devel_generate');
 
   $course_types = array_filter($form_state['values']['course_types']);
   $course_limit = $form_state['values']['course_limit'];
@@ -103,7 +103,7 @@ function course_generate($course_type, $course_object_types, $course_object_limi
   );
 
   // Populate all core fields on behalf of field.module
-  module_load_include('inc', 'devel_generate', 'devel_generate.fields');
+  \Drupal::moduleHandler()->loadInclude('devel_generate', 'inc', 'devel_generate.fields');
   devel_generate_fields($node, 'node', $node->type);
   unset($node->og_group_ref);
   node_save($node);
diff --git a/course.module b/course.module
index de01962..f7cab80 100644
--- a/course.module
+++ b/course.module
@@ -90,7 +90,7 @@ function course_ajaj_fulfullment_check($node, $courseObject, $js = FALSE) {
   if (course_node_is_course($node)) {
     course_set_context($node);
   }
-  module_load_include('inc', 'course', 'includes/course.block');
+  \Drupal::moduleHandler()->loadInclude('course', 'inc', 'includes/course.block');
 
   course_get_course($node);
   $block = block_load('course', 'navigation');
diff --git a/modules/course_book/src/EventSubscriber/CourseBookEventSubscriber.php b/modules/course_book/src/EventSubscriber/CourseBookEventSubscriber.php
index b3e6e9b..bc34445 100644
--- a/modules/course_book/src/EventSubscriber/CourseBookEventSubscriber.php
+++ b/modules/course_book/src/EventSubscriber/CourseBookEventSubscriber.php
@@ -10,7 +10,7 @@ use function course_get_course_object;
 
 class CourseBookEventSubscriber implements EventSubscriberInterface {
 
-  public static function getSubscribedEvents() {
+  public static function getSubscribedEvents(): array {
     return [
       KernelEvents::REQUEST => ['onRequest', 28],
     ];
diff --git a/modules/course_content/src/Course/Object/CourseObjectNode.php b/modules/course_content/src/Course/Object/CourseObjectNode.php
index cfd68a3..74af9a7 100644
--- a/modules/course_content/src/Course/Object/CourseObjectNode.php
+++ b/modules/course_content/src/Course/Object/CourseObjectNode.php
@@ -181,7 +181,7 @@ abstract class CourseObjectNode extends CourseObjectEntity {
   function preSave(EntityStorageInterface $storage, $update = TRUE) {
 
     if ($this->getOption('clone_and_reference')) {
-      module_load_include('inc', 'clone', 'clone.pages');
+      \Drupal::moduleHandler()->loadInclude('clone', 'inc', 'clone.pages');
       $new_nid = clone_node_save($this->getOption('instance'));
       $this->setInstanceId($new_nid);
       $this->setOption('clone_and_reference', 0);
diff --git a/modules/course_content/src/EventSubscriber/CourseContentEventSubscriber.php b/modules/course_content/src/EventSubscriber/CourseContentEventSubscriber.php
index 54015a3..a48324b 100644
--- a/modules/course_content/src/EventSubscriber/CourseContentEventSubscriber.php
+++ b/modules/course_content/src/EventSubscriber/CourseContentEventSubscriber.php
@@ -16,7 +16,7 @@ class CourseContentEventSubscriber implements EventSubscriberInterface {
    *
    * Set the priority to 28 so we run in time for the dynamic cache.
    */
-  public static function getSubscribedEvents() {
+  public static function getSubscribedEvents(): array {
     return [
       KernelEvents::REQUEST => ['onRequest', 28],
     ];
diff --git a/modules/course_poll/src/Plugin/course/CourseObject/CourseObjectPoll.php b/modules/course_poll/src/Plugin/course/CourseObject/CourseObjectPoll.php
index c341427..1036951 100644
--- a/modules/course_poll/src/Plugin/course/CourseObject/CourseObjectPoll.php
+++ b/modules/course_poll/src/Plugin/course/CourseObject/CourseObjectPoll.php
@@ -84,7 +84,7 @@ class CourseObjectPoll extends CourseObjectEntity {
   }
 
   public function getReport($key) {
-    module_load_include('inc', 'poll', 'poll.pages');
+    \Drupal::moduleHandler()->loadInclude('poll', 'inc', 'poll.pages');
     switch ($key) {
       case 'results':
         return array(
diff --git a/modules/course_quiz/src/Plugin/course/CourseObject/CourseObjectQuiz.php b/modules/course_quiz/src/Plugin/course/CourseObject/CourseObjectQuiz.php
index 7d6ebc0..2ae7a5c 100644
--- a/modules/course_quiz/src/Plugin/course/CourseObject/CourseObjectQuiz.php
+++ b/modules/course_quiz/src/Plugin/course/CourseObject/CourseObjectQuiz.php
@@ -158,7 +158,7 @@ class CourseObjectQuiz extends CourseObjectEntity {
 
   public function getReport($key) {
 
-    module_load_include('inc', 'quiz', 'quiz.admin');
+    \Drupal::moduleHandler()->loadInclude('quiz', 'inc', 'quiz.admin');
     switch ($key) {
       case 'analysis':
         $path = "/course/{$this->getCourse()->id()}/enrollments/objects/{$this->get('coid')->getValue()[0]['value']}/analysis";
@@ -198,7 +198,7 @@ class CourseObjectQuiz extends CourseObjectEntity {
           'content' => $out,
         );
       case 'statistics':
-        module_load_include('inc', 'quiz_stats', 'quiz_stats.admin');
+        \Drupal::moduleHandler()->loadInclude('quiz_stats', 'inc', 'quiz_stats.admin');
         return array(
           'title' => t('Quiz statistics'),
           'content' => quiz_stats_get_adv_stats($this->getNode()->vid),
diff --git a/modules/course_webform/src/EventSubscriber/CourseWebformEventSubscriber.php b/modules/course_webform/src/EventSubscriber/CourseWebformEventSubscriber.php
index 44c5e6e..e3b7c8c 100644
--- a/modules/course_webform/src/EventSubscriber/CourseWebformEventSubscriber.php
+++ b/modules/course_webform/src/EventSubscriber/CourseWebformEventSubscriber.php
@@ -9,7 +9,7 @@ use Symfony\Component\HttpKernel\KernelEvents;
 
 class CourseWebformEventSubscriber implements EventSubscriberInterface {
 
-  public static function getSubscribedEvents() {
+  public static function getSubscribedEvents(): array {
     return [
       KernelEvents::REQUEST => ['onRequest', 28],
     ];
diff --git a/src/EventSubscriber/CourseEventSubscriber.php b/src/EventSubscriber/CourseEventSubscriber.php
index 963f90a..81ff93d 100644
--- a/src/EventSubscriber/CourseEventSubscriber.php
+++ b/src/EventSubscriber/CourseEventSubscriber.php
@@ -11,7 +11,7 @@ use function course_get_course_object;
 
 class CourseEventSubscriber implements EventSubscriberInterface {
 
-  public static function getSubscribedEvents() {
+  public static function getSubscribedEvents(): array {
     return [
       // Set priority to 28 so we can get around the page cache.
       KernelEvents::REQUEST => ['onRequest', 28],
diff --git a/tests/src/Functional/CourseEnrollmentTest.php b/tests/src/Functional/CourseEnrollmentTest.php
index bc8b88a..1744c13 100644
--- a/tests/src/Functional/CourseEnrollmentTest.php
+++ b/tests/src/Functional/CourseEnrollmentTest.php
@@ -166,8 +166,8 @@ class CourseEnrollmentTest extends CourseTestBase {
 
     // Check if field shows up and user is not yet enrolled.
     $this->drupalGet("course/{$courseA->id()}/take");
-    $this->assertFieldById('edit-enrollment-field-a-0-value');
-    $this->assertNoFieldById('edit-enrollment-field-b-0-value');
+    $this->assertSession()->fieldValueEquals('edit-enrollment-field-a-0-value', '');
+    $this->assertSession()->fieldNotExists('edit-enrollment-field-b-0-value');
     $enrollment = $courseA->getEnrollment($this->student_user);
     $this->assertEmpty($enrollment);
     $this->submitForm([], t('Save'));
@@ -177,15 +177,15 @@ class CourseEnrollmentTest extends CourseTestBase {
 
     // Check that a different field is on course B
     $this->drupalGet("course/{$courseB->id()}/take");
-    $this->assertFieldById('edit-enrollment-field-b-0-value');
-    $this->assertNoFieldById('edit-enrollment-field-a-0-value');
+    $this->assertSession()->fieldValueEquals('edit-enrollment-field-b-0-value', '');
+    $this->assertSession()->fieldNotExists('edit-enrollment-field-a-0-value');
 
     // Mark field B to not show on enrollment.
     $instanceb->setThirdPartySetting('course', 'show_field', FALSE);
     $instanceb->save();
     $this->drupalGet("course/{$courseB->id()}/take");
-    $this->assertNoFieldById('edit-enrollment-field-a-0-value');
-    $this->assertNoFieldById('edit-enrollment-field-b-0-value');
+    $this->assertSession()->fieldNotExists('edit-enrollment-field-a-0-value');
+    $this->assertSession()->fieldNotExists('edit-enrollment-field-b-0-value');
   }
 
 }