diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ddfcfcc18cefdce73f8134b2751415580b46ea28..ac71a2f538f24116869ec3474b2b2580908941af 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,106 +1,32 @@
 ################
-# DrupalCI GitLabCI template
+# GitLabCI template for Drupal projects.
 #
-# Gitlab-ci.yml to replicate DrupalCI testing for Contrib
-#
-# With thanks to:
-#   * The GitLab Acceleration Initiative participants
-#   * DrupalSpoons
-################
-
-################
-# Guidelines
-#
-# This template is designed to give any Contrib maintainer everything they need to test, without requiring modification. It is also designed to keep up to date with Core Development automatically through the use of include files that can be centrally maintained.
-#
-# However, you can modify this template if you have additional needs for your project.
-################
-
-################
-# Includes
-#
-# Additional configuration can be provided through includes.
-# One advantage of include files is that if they are updated upstream, the changes affect all pipelines using that include.
-#
-# Includes can be overridden by re-declaring anything provided in an include, here in gitlab-ci.yml
-# https://docs.gitlab.com/ee/ci/yaml/includes.html#override-included-configuration-values
+# This template is designed to give any Contrib maintainer everything they need to test, without requiring modification.
+# It is also designed to keep up to date with Core Development automatically through the use of include files that can be centrally maintained.
+# As long as you include the project, ref and three files below, any future updates added by the Drupal Association will be used in your
+# pipelines automatically. However, you can modify this template if you have additional needs for your project.
+# The full documentation is on https://project.pages.drupalcode.org/gitlab_templates/
 ################
 
+# For information on alternative values for 'ref' see https://project.pages.drupalcode.org/gitlab_templates/info/templates-version/
+# To test a Drupal 7 project, change the first include filename from .main.yml to .main-d7.yml
 include:
-  ################
-  # DrupalCI includes:
-  # As long as you include this, any future includes added by the Drupal Association will be accessible to your pipelines automatically.
-  # View these include files at https://git.drupalcode.org/project/gitlab_templates/
-  ################
   - project: $_GITLAB_TEMPLATES_REPO
-    # "ref" value can be:
-    # - Recommended (default) - `ref: $_GITLAB_TEMPLATES_REF` - The Drupal Association will update this value to the recommended tag for contrib.
-    # - Latest - `ref: main` - Get the latest additions and bug fixes as they are merged into the templates.
-    # - Minor or Major latests - `ref: 1.x-latest` or `ref: 1.0.x-latest` - Get the latest additions within a minor (mostly bugfixes) or major (bugs and new features).
-    # - Fixed tag - `ref: 1.0.1` - Set the value to a known tag. This will not get any updates.
-    # If you change the default value of ref, you should set the _CURL_TEMPLATES_REF variable in the variables section to be the same as set here.
     ref: $_GITLAB_TEMPLATES_REF
     file:
       - "/includes/include.drupalci.main.yml"
-      # For Drupal 7, remove the above line and uncomment the below.
-      # - "/includes/include.drupalci.main-d7.yml"
       - "/includes/include.drupalci.variables.yml"
       - "/includes/include.drupalci.workflows.yml"
-#
+
 ################
-# Pipeline configuration variables
-#
-# These are the variables provided to the Run Pipeline form that a user may want to override.
-#
-# Docs at https://git.drupalcode.org/project/gitlab_templates/-/blob/main/includes/include.drupalci.variables.yml
+# Pipeline configuration variables are defined with default values and descriptions in the file
+# https://git.drupalcode.org/project/gitlab_templates/-/blob/main/includes/include.drupalci.variables.yml
+# Uncomment the lines below if you want to override any of the variables. The following is just an example.
 ################
 # variables:
 #   SKIP_ESLINT: '1'
 #   OPT_IN_TEST_NEXT_MAJOR: '1'
 #   _CURL_TEMPLATES_REF: 'main'
 
-###################################################################################
-#
-#                                        *
-#                                       /(
-#                                      ((((,
-#                                    /(((((((
-#                                   ((((((((((*
-#                                ,(((((((((((((((
-#                              ,(((((((((((((((((((
-#                            ((((((((((((((((((((((((*
-#                         *(((((((((((((((((((((((((((((
-#                       ((((((((((((((((((((((((((((((((((*
-#                    *((((((((((((((((((  .((((((((((((((((((
-#                  ((((((((((((((((((.       /(((((((((((((((((*
-#                /(((((((((((((((((            .(((((((((((((((((,
-#             ,((((((((((((((((((                 ((((((((((((((((((
-#           .((((((((((((((((((((                   .(((((((((((((((((
-#          (((((((((((((((((((((((                     ((((((((((((((((/
-#        (((((((((((((((((((((((((((/                    ,(((((((((((((((*
-#      .((((((((((((((/  /(((((((((((((.                   ,(((((((((((((((
-#     *((((((((((((((      ,(((((((((((((/                   *((((((((((((((.
-#    ((((((((((((((,          /(((((((((((((.                  ((((((((((((((,
-#   (((((((((((((/              ,(((((((((((((*                 ,(((((((((((((,
-#  *(((((((((((((                .(((((((((((((((                ,(((((((((((((
-#  ((((((((((((/                /((((((((((((((((((.              ,((((((((((((/
-# (((((((((((((              *(((((((((((((((((((((((*             *((((((((((((
-# (((((((((((((            ,(((((((((((((..(((((((((((((           *((((((((((((
-# ((((((((((((,          /((((((((((((*      /((((((((((((/         ((((((((((((
-# (((((((((((((        /((((((((((((/          (((((((((((((*       ((((((((((((
-# (((((((((((((/     /((((((((((((               ,((((((((((((,    *((((((((((((
-#  ((((((((((((((  *(((((((((((/                   *((((((((((((.  ((((((((((((/
-#  *((((((((((((((((((((((((((,                      /(((((((((((((((((((((((((
-#   (((((((((((((((((((((((((                         ((((((((((((((((((((((((,
-#   .(((((((((((((((((((((((/                         ,(((((((((((((((((((((((
-#     ((((((((((((((((((((((/                         ,(((((((((((((((((((((/
-#      *(((((((((((((((((((((                         (((((((((((((((((((((,
-#       ,(((((((((((((((((((((,                      ((((((((((((((((((((/
-#         ,(((((((((((((((((((((*                  /((((((((((((((((((((
-#            ((((((((((((((((((((((,           ,/((((((((((((((((((((,
-#              ,(((((((((((((((((((((((((((((((((((((((((((((((((((
-#                 .(((((((((((((((((((((((((((((((((((((((((((((
-#                     .((((((((((((((((((((((((((((((((((((,.
-#                          .,(((((((((((((((((((((((((.
-#
-###################################################################################
+phpcs:
+  allow_failure: false
diff --git a/modules/recurring_events_ical/tests/src/Kernel/EventICalTest.php b/modules/recurring_events_ical/tests/src/Kernel/EventICalTest.php
index 35549bb12c9b950fa2d80e453cdf805b30df547a..6431552af509429f0afaf80f6f24a9933f6cebdb 100644
--- a/modules/recurring_events_ical/tests/src/Kernel/EventICalTest.php
+++ b/modules/recurring_events_ical/tests/src/Kernel/EventICalTest.php
@@ -3,8 +3,8 @@
 namespace Drupal\Tests\recurring_events_ical\Kernel;
 
 use Drupal\Core\Datetime\DrupalDateTime;
-use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\KernelTests\KernelTestBase;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\recurring_events\Entity\EventSeries;
 
 /**
diff --git a/modules/recurring_events_registration/recurring_events_registration.api.php b/modules/recurring_events_registration/recurring_events_registration.api.php
index 01097a0c95de715c7f39e4c3a35b3f5d9d63dd98..c201179fd81a4c5917a1fd8dddc53dbdb73808c5 100644
--- a/modules/recurring_events_registration/recurring_events_registration.api.php
+++ b/modules/recurring_events_registration/recurring_events_registration.api.php
@@ -17,7 +17,7 @@ use Drupal\recurring_events_registration\Entity\RegistrantInterface;
  * instance of Drupal\recurring_events_registration\Entity\Registrant for the
  * specified event, which can be retrieved from the registrant entity.
  *
- * @param Drupal\recurring_events_registration\Entity\Registrant $registrant
+ * @param \Drupal\recurring_events_registration\Entity\Registrant $registrant
  *   The default selected registrant.
  *
  * @return \Drupal\recurring_events_registration\Entity\Registrant
@@ -35,7 +35,7 @@ function hook_recurring_events_registration_first_waitlist_alter(Registrant $reg
  *
  * @param bool $send_email
  *   Whether the notification email is sent.
- * @param Drupal\recurring_events_registration\Entity\RegistrantInterface $registrant
+ * @param \Drupal\recurring_events_registration\Entity\RegistrantInterface $registrant
  *   The registrant entity.
  */
 function hook_recurring_events_registration_send_notification_alter(bool &$send_email, RegistrantInterface $registrant) {
diff --git a/modules/recurring_events_registration/src/AccessHandler.php b/modules/recurring_events_registration/src/AccessHandler.php
index 3ae097802406eedf6529e307285961ab2794d5ab..e16e70723624daa2a40740960ae51ce221d4f60d 100644
--- a/modules/recurring_events_registration/src/AccessHandler.php
+++ b/modules/recurring_events_registration/src/AccessHandler.php
@@ -50,7 +50,7 @@ class AccessHandler {
    *   The translation interface.
    * @param \Drupal\recurring_events_registration\RegistrationCreationService $creation_service
    *   The registration creation service.
-   * @param Drupal\Core\Routing\CurrentRouteMatch $route_match
+   * @param \Drupal\Core\Routing\CurrentRouteMatch $route_match
    *   The current route match.
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
    *   The entity type manager service.
@@ -100,7 +100,7 @@ class AccessHandler {
   /**
    * Access control based on whether the account has the right permission.
    *
-   * @param Drupal\Core\Session\AccountInterface $account
+   * @param \Drupal\Core\Session\AccountInterface $account
    *   The current route.
    *
    * @return bool
diff --git a/modules/recurring_events_registration/src/Controller/RegistrantController.php b/modules/recurring_events_registration/src/Controller/RegistrantController.php
index e28bf6b97b6c3c06de11879f69b879588e0e7c66..41b38edcc8c025a1850fb126e25acf2171e995b4 100644
--- a/modules/recurring_events_registration/src/Controller/RegistrantController.php
+++ b/modules/recurring_events_registration/src/Controller/RegistrantController.php
@@ -68,7 +68,7 @@ class RegistrantController extends ControllerBase implements ContainerInjectionI
   /**
    * Check if registration is enabled.
    *
-   * @param Drupal\recurring_events\Entity\EventInstance $eventinstance
+   * @param \Drupal\recurring_events\Entity\EventInstance $eventinstance
    *   The eventinstance entity.
    *
    * @return \Drupal\Core\Access\AccessResultInterface
@@ -91,7 +91,7 @@ class RegistrantController extends ControllerBase implements ContainerInjectionI
   /**
    * Check if the user can contact the registrants.
    *
-   * @param Drupal\recurring_events\Entity\EventInstance $eventinstance
+   * @param \Drupal\recurring_events\Entity\EventInstance $eventinstance
    *   The eventinstance entity.
    *
    * @return \Drupal\Core\Access\AccessResultInterface
@@ -108,7 +108,7 @@ class RegistrantController extends ControllerBase implements ContainerInjectionI
   /**
    * Return a dynamic page title for a Registrant.
    *
-   * @param Drupal\recurring_events_registration\Entity\RegistrantInterface $registrant
+   * @param \Drupal\recurring_events_registration\Entity\RegistrantInterface $registrant
    *   The entity for which to generate a page title.
    *
    * @return string
diff --git a/modules/recurring_events_registration/src/Entity/Registrant.php b/modules/recurring_events_registration/src/Entity/Registrant.php
index ae0b3ccc3bffd23dc5d21f3c60c4955bca06634a..57e30517e9fe49db7a574b18b8b1057b97c3fa93 100644
--- a/modules/recurring_events_registration/src/Entity/Registrant.php
+++ b/modules/recurring_events_registration/src/Entity/Registrant.php
@@ -287,7 +287,7 @@ class Registrant extends EditorialContentEntityBase implements RegistrantInterfa
   /**
    * Set the event series ID.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The event series entity.
    *
    * @return \Drupal\recurring_events_registration\Entity\RegistrantInterface
@@ -308,7 +308,7 @@ class Registrant extends EditorialContentEntityBase implements RegistrantInterfa
   /**
    * Set the event ID.
    *
-   * @param Drupal\recurring_events\Entity\EventInstance $event
+   * @param \Drupal\recurring_events\Entity\EventInstance $event
    *   The eventinstance entity.
    *
    * @return \Drupal\recurring_events_registration\Entity\RegistrantInterface
diff --git a/modules/recurring_events_registration/src/Form/RegistrantDeleteForm.php b/modules/recurring_events_registration/src/Form/RegistrantDeleteForm.php
index 04d3da627c0fa3704426d54637a6af578748e2e1..a72de862e213c2452f4eb3d43032dbc916ee44c2 100644
--- a/modules/recurring_events_registration/src/Form/RegistrantDeleteForm.php
+++ b/modules/recurring_events_registration/src/Form/RegistrantDeleteForm.php
@@ -46,9 +46,9 @@ class RegistrantDeleteForm extends ContentEntityDeleteForm {
    *
    * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
    *   The entity repository service.
-   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
+   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface|null $entity_type_bundle_info
    *   The entity type bundle service.
-   * @param \Drupal\Component\Datetime\TimeInterface $time
+   * @param \Drupal\Component\Datetime\TimeInterface|null $time
    *   The time service.
    * @param \Drupal\Core\Messenger\Messenger $messenger
    *   The messenger service.
@@ -57,7 +57,7 @@ class RegistrantDeleteForm extends ContentEntityDeleteForm {
    * @param \Drupal\recurring_events_registration\RegistrationCreationService $creation_service
    *   The creation service.
    */
-  public function __construct(EntityRepositoryInterface $entity_repository, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL, Messenger $messenger, Renderer $renderer, RegistrationCreationService $creation_service) {
+  public function __construct(EntityRepositoryInterface $entity_repository, ?EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, ?TimeInterface $time = NULL, Messenger $messenger, Renderer $renderer, RegistrationCreationService $creation_service) {
     parent::__construct($entity_repository, $entity_type_bundle_info, $time);
     $this->messenger = $messenger;
     $this->renderer = $renderer;
diff --git a/modules/recurring_events_registration/src/Form/RegistrantForm.php b/modules/recurring_events_registration/src/Form/RegistrantForm.php
index 87c54f714dbc9895f704bb9083747b4f946f194d..2a8debd9eb5cf4b359b644e69a77363e3a771f6d 100644
--- a/modules/recurring_events_registration/src/Form/RegistrantForm.php
+++ b/modules/recurring_events_registration/src/Form/RegistrantForm.php
@@ -4,7 +4,6 @@ namespace Drupal\recurring_events_registration\Form;
 
 use Drupal\Component\Datetime\TimeInterface;
 use Drupal\Component\Render\FormattableMarkup;
-use Drupal\content_moderation\ModerationInformation;
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Entity\ContentEntityForm;
 use Drupal\Core\Entity\EntityFieldManager;
@@ -17,6 +16,7 @@ use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Routing\TrustedRedirectResponse;
 use Drupal\Core\Session\AccountProxyInterface;
 use Drupal\Core\Url;
+use Drupal\content_moderation\ModerationInformation;
 use Drupal\recurring_events_registration\NotificationService;
 use Drupal\recurring_events_registration\RegistrationCreationService;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -136,7 +136,7 @@ class RegistrantForm extends ContentEntityForm {
    *   The entity type manager service.
    * @param \Drupal\recurring_events_registration\NotificationService $notification_service
    *   The registration notification service.
-   * @param \Drupal\content_moderation\ModerationInformation $moderation_information
+   * @param \Drupal\content_moderation\ModerationInformation|null $moderation_information
    *   The moderation information service.
    */
   public function __construct(
@@ -151,7 +151,8 @@ class RegistrantForm extends ContentEntityForm {
     RouteMatchInterface $route_match,
     EntityTypeManagerInterface $entity_type_manager,
     NotificationService $notification_service,
-    ModerationInformation $moderation_information = NULL) {
+    ?ModerationInformation $moderation_information = NULL,
+  ) {
     $this->messenger = $messenger;
     $this->creationService = $creation_service;
     $this->currentUser = $current_user;
diff --git a/modules/recurring_events_registration/src/Form/RegistrantSettingsForm.php b/modules/recurring_events_registration/src/Form/RegistrantSettingsForm.php
index c816f37c075df67c83d016f44365ec5710aa52c8..118dc856253e905e52aae8c406c50528435319c4 100644
--- a/modules/recurring_events_registration/src/Form/RegistrantSettingsForm.php
+++ b/modules/recurring_events_registration/src/Form/RegistrantSettingsForm.php
@@ -63,7 +63,7 @@ class RegistrantSettingsForm extends ConfigFormBase {
     NotificationService $notification_service,
     RegistrationCreationService $creation_service,
     ModuleHandlerInterface $module_handler,
-    RouteBuilderInterface $route_builder
+    RouteBuilderInterface $route_builder,
   ) {
     $this->notificationService = $notification_service;
     $this->creationService = $creation_service;
diff --git a/modules/recurring_events_registration/src/Plugin/ComputedField/AvailabilityCount.php b/modules/recurring_events_registration/src/Plugin/ComputedField/AvailabilityCount.php
index 6992bee4ff83e1a86f8f09317b484190df7b1811..66d3e66d3aac5c33867e3a3600c84d7705fea7b8 100644
--- a/modules/recurring_events_registration/src/Plugin/ComputedField/AvailabilityCount.php
+++ b/modules/recurring_events_registration/src/Plugin/ComputedField/AvailabilityCount.php
@@ -26,7 +26,7 @@ class AvailabilityCount extends FieldItemList {
   /**
    * {@inheritdoc}
    */
-  public function __construct(DataDefinitionInterface $definition, $name = NULL, TypedDataInterface $parent = NULL) {
+  public function __construct(DataDefinitionInterface $definition, $name = NULL, ?TypedDataInterface $parent = NULL) {
     parent::__construct($definition, $name, $parent);
     // @todo Look for a better way to inject this service.
     $this->requestStack = \Drupal::service('request_stack');
diff --git a/modules/recurring_events_registration/src/Plugin/ComputedField/RegistrationCount.php b/modules/recurring_events_registration/src/Plugin/ComputedField/RegistrationCount.php
index a952b000d4319aa5fdab00474eb9dcde5d0aa373..4c3b6c4f6ddc402550988a3632a336b0bb044bb4 100644
--- a/modules/recurring_events_registration/src/Plugin/ComputedField/RegistrationCount.php
+++ b/modules/recurring_events_registration/src/Plugin/ComputedField/RegistrationCount.php
@@ -26,7 +26,7 @@ class RegistrationCount extends FieldItemList {
   /**
    * {@inheritdoc}
    */
-  public function __construct(DataDefinitionInterface $definition, $name = NULL, TypedDataInterface $parent = NULL) {
+  public function __construct(DataDefinitionInterface $definition, $name = NULL, ?TypedDataInterface $parent = NULL) {
     parent::__construct($definition, $name, $parent);
     // @todo Look for a better way to inject this service.
     $this->requestStack = \Drupal::service('request_stack');
diff --git a/modules/recurring_events_registration/src/Plugin/ComputedField/WaitlistCount.php b/modules/recurring_events_registration/src/Plugin/ComputedField/WaitlistCount.php
index fc88ebf08dd4dc57365254dcf102774265f20577..3ef84d648c328024f38e6b6939a40dc65821a519 100644
--- a/modules/recurring_events_registration/src/Plugin/ComputedField/WaitlistCount.php
+++ b/modules/recurring_events_registration/src/Plugin/ComputedField/WaitlistCount.php
@@ -26,7 +26,7 @@ class WaitlistCount extends FieldItemList {
   /**
    * {@inheritdoc}
    */
-  public function __construct(DataDefinitionInterface $definition, $name = NULL, TypedDataInterface $parent = NULL) {
+  public function __construct(DataDefinitionInterface $definition, $name = NULL, ?TypedDataInterface $parent = NULL) {
     parent::__construct($definition, $name, $parent);
     // @todo Look for a better way to inject this service.
     $this->requestStack = \Drupal::service('request_stack');
diff --git a/modules/recurring_events_registration/src/Plugin/views/access/EventRegistrationListAccess.php b/modules/recurring_events_registration/src/Plugin/views/access/EventRegistrationListAccess.php
index 964981edb32176845072d5b89368b2871ce1931b..a757c98718ce6d980852913cbfe01f31684c2374 100644
--- a/modules/recurring_events_registration/src/Plugin/views/access/EventRegistrationListAccess.php
+++ b/modules/recurring_events_registration/src/Plugin/views/access/EventRegistrationListAccess.php
@@ -37,7 +37,7 @@ class EventRegistrationListAccess extends AccessPluginBase {
    *   The plugin_id for the plugin instance.
    * @param mixed $plugin_definition
    *   The plugin implementation definition.
-   * @param Drupal\recurring_events_registration\AccessHandler $access_handler
+   * @param \Drupal\recurring_events_registration\AccessHandler $access_handler
    *   The access handler.
    */
   public function __construct(array $configuration, $plugin_id, $plugin_definition, AccessHandler $access_handler) {
diff --git a/modules/recurring_events_registration/src/RegistrantAccessControlHandler.php b/modules/recurring_events_registration/src/RegistrantAccessControlHandler.php
index 5b2a59ceb430c7ca26e487cb09cb59182351ddda..59ba987323fae5c37810b8c17d6f4ca97836c1f0 100644
--- a/modules/recurring_events_registration/src/RegistrantAccessControlHandler.php
+++ b/modules/recurring_events_registration/src/RegistrantAccessControlHandler.php
@@ -120,11 +120,11 @@ class RegistrantAccessControlHandler extends EntityAccessControlHandler implemen
   /**
    * Check if the user can edit or delete this registrant anonymously.
    *
-   * @param Drupal\Core\Entity\EntityInterface $registrant
+   * @param \Drupal\Core\Entity\EntityInterface $registrant
    *   The registrant to be edited.
    * @param string $operation
    *   The operation being attempted.
-   * @param Drupal\Core\Session\AccountInterface $account
+   * @param \Drupal\Core\Session\AccountInterface $account
    *   The user attempting to gain access.
    *
    * @return \Drupal\Core\Access\AccessResultInterface
diff --git a/modules/recurring_events_registration/src/RegistrationCreationService.php b/modules/recurring_events_registration/src/RegistrationCreationService.php
index 138cb48ceabfceb424bdaa2453a5ed28abe1ab44..cadbc6a83c4ad9524a342f8464f698f11d1eb9b0 100644
--- a/modules/recurring_events_registration/src/RegistrationCreationService.php
+++ b/modules/recurring_events_registration/src/RegistrationCreationService.php
@@ -129,7 +129,7 @@ class RegistrationCreationService {
   /**
    * Set the event entities.
    *
-   * @param Drupal\recurring_events\Entity\EventInstance $event_instance
+   * @param \Drupal\recurring_events\Entity\EventInstance $event_instance
    *   The event instance.
    */
   public function setEventInstance(EventInstance $event_instance) {
@@ -140,7 +140,7 @@ class RegistrationCreationService {
   /**
    * Set the event series, helpful to get a fresh copy of the entity.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event_series
+   * @param \Drupal\recurring_events\Entity\EventSeries $event_series
    *   The event series.
    */
   public function setEventSeries(EventSeries $event_series) {
diff --git a/modules/recurring_events_registration/src/Routing/RouteSubscriber.php b/modules/recurring_events_registration/src/Routing/RouteSubscriber.php
index b0aa3798ee310d123962add77fb745cce23264f4..202ddc13527faed5063425ab25ee36db60eab489 100644
--- a/modules/recurring_events_registration/src/Routing/RouteSubscriber.php
+++ b/modules/recurring_events_registration/src/Routing/RouteSubscriber.php
@@ -24,9 +24,7 @@ class RouteSubscriber extends RouteSubscriberBase {
    * @param \Drupal\Core\Config\ConfigFactoryInterface $configFactory
    *   The config factory.
    */
-  public function __construct(
-    ConfigFactoryInterface $configFactory
-  ) {
+  public function __construct(ConfigFactoryInterface $configFactory) {
     $this->configFactory = $configFactory;
   }
 
diff --git a/modules/recurring_events_registration/tests/src/Kernel/RegistrantControllerTest.php b/modules/recurring_events_registration/tests/src/Kernel/RegistrantControllerTest.php
index d16a1feca77008f1795be9c76527631b8429f654..eed855ff9ef0c51c18d6a454fd558762833b20dd 100644
--- a/modules/recurring_events_registration/tests/src/Kernel/RegistrantControllerTest.php
+++ b/modules/recurring_events_registration/tests/src/Kernel/RegistrantControllerTest.php
@@ -5,8 +5,8 @@ declare(strict_types=1);
 namespace Drupal\Tests\recurring_events_registration\Kernel;
 
 use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\KernelTests\KernelTestBase;
+use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\recurring_events\Entity\EventInstance;
 use Drupal\recurring_events_registration\Controller\RegistrantController;
 use Drupal\recurring_events_registration\Entity\Registrant;
diff --git a/recurring_events.api.php b/recurring_events.api.php
index f6fc350661e76a8b8ecb668bcc56dc18992ae944..5dcdf8d8bdce467a48cdb44b390ace461e903c01 100644
--- a/recurring_events.api.php
+++ b/recurring_events.api.php
@@ -78,11 +78,11 @@ function hook_recurring_events_event_instance_alter(array &$event_instance = [])
 /**
  * Alter the active EventInstanceCreator plugin.
  *
- * @param Drupal\recurring_events\EventInstanceCreatorInterface $active_plugin
+ * @param \Drupal\recurring_events\EventInstanceCreatorInterface $active_plugin
  *   The active plugin to use.
- * @param Drupal\recurring_events\EventInstanceCreatorPluginManager $plugin_manager
+ * @param \Drupal\recurring_events\EventInstanceCreatorPluginManager $plugin_manager
  *   The plugin manager to discover plugins.
- * @param Drupal\recurring_events\Entity\EventSeries $series
+ * @param \Drupal\recurring_events\Entity\EventSeries $series
  *   The event series for which we need to create instances.
  */
 function hook_recurring_events_event_instance_creator_plugin_alter(EventInstanceCreatorInterface &$active_plugin, EventInstanceCreatorPluginManager $plugin_manager, EventSeries $series) {
@@ -181,7 +181,7 @@ function hook_recurring_events_save_pre_instances_deletion_alter(array &$instanc
  * and recreate them. This hook allows you to execute code prior to the deletion
  * of those instances.
  *
- * @param Drupal\recurring_events\Entity\EventSeries $event_series
+ * @param \Drupal\recurring_events\Entity\EventSeries $event_series
  *   The eventseries being altered.
  */
 function hook_recurring_events_save_pre_instances_deletion(EventSeries $event_series) {
@@ -195,7 +195,7 @@ function hook_recurring_events_save_pre_instances_deletion(EventSeries $event_se
  * and recreate them. This hook allows you to execute code after the deletion
  * of those instances.
  *
- * @param Drupal\recurring_events\Entity\EventSeries $event_series
+ * @param \Drupal\recurring_events\Entity\EventSeries $event_series
  *   The eventseries being altered.
  */
 function hook_recurring_events_save_post_instances_deletion(EventSeries $event_series) {
@@ -209,9 +209,9 @@ function hook_recurring_events_save_post_instances_deletion(EventSeries $event_s
  * and recreate them. This hook allows you to execute code prior to the deletion
  * of each instance.
  *
- * @param Drupal\recurring_events\Entity\EventSeries $event_series
+ * @param \Drupal\recurring_events\Entity\EventSeries $event_series
  *   The eventseries being altered.
- * @param Drupal\recurring_events\Entity\EventInstance $event_instance
+ * @param \Drupal\recurring_events\Entity\EventInstance $event_instance
  *   The event instance being deleted.
  */
 function hook_recurring_events_save_pre_instance_deletion(EventSeries $event_series, EventInstance $event_instance) {
@@ -225,9 +225,9 @@ function hook_recurring_events_save_pre_instance_deletion(EventSeries $event_ser
  * and recreate them. This hook allows you to execute code after the deletion
  * of each instance.
  *
- * @param Drupal\recurring_events\Entity\EventSeries $event_series
+ * @param \Drupal\recurring_events\Entity\EventSeries $event_series
  *   The eventseries being altered.
- * @param Drupal\recurring_events\Entity\EventInstance $event_instance
+ * @param \Drupal\recurring_events\Entity\EventInstance $event_instance
  *   The event instance being deleted.
  */
 function hook_recurring_events_save_post_instance_deletion(EventSeries $event_series, EventInstance $event_instance) {
diff --git a/recurring_events.module b/recurring_events.module
index fb80cabe6735b4a2d85d603af4a3937144607db0..4902fe0f2b9d3de40891e9b98c8fbbd051a229af 100644
--- a/recurring_events.module
+++ b/recurring_events.module
@@ -676,7 +676,7 @@ function recurring_events_recurring_events_event_instances_pre_create_alter(arra
 /**
  * Implements callback_allowed_values_function().
  */
-function recurring_events_allowed_values_function(FieldStorageDefinitionInterface $definition, FieldableEntityInterface $entity = NULL) {
+function recurring_events_allowed_values_function(FieldStorageDefinitionInterface $definition, ?FieldableEntityInterface $entity = NULL) {
   $values = ['custom' => t('Custom/Single Event')];
   $fields = \Drupal::service('entity_field.manager')->getBaseFieldDefinitions('eventseries');
   foreach ($fields as $field) {
diff --git a/src/Controller/EventInstanceController.php b/src/Controller/EventInstanceController.php
index 93d69a1a354766a096ba5ab0ab5e3429a08a78c7..108654827fe677e6157f102e885507208bbf134c 100644
--- a/src/Controller/EventInstanceController.php
+++ b/src/Controller/EventInstanceController.php
@@ -63,7 +63,7 @@ class EventInstanceController extends ControllerBase implements ContainerInjecti
    *   The renderer service.
    * @param \Drupal\system\SystemManager $systemManager
    *   System manager service.
-   * @param Drupal\Core\Language\LanguageManagerInterface $language_manager
+   * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
    *   The language manager service.
    */
   public function __construct(DateFormatterInterface $date_formatter, RendererInterface $renderer, SystemManager $systemManager, LanguageManagerInterface $language_manager) {
diff --git a/src/EventCreationService.php b/src/EventCreationService.php
index 7eecac8bae9993340c5eeb14336686ecab7189b8..d4b23d78b4d55aa0b6304928fb5ebb1043361421 100644
--- a/src/EventCreationService.php
+++ b/src/EventCreationService.php
@@ -144,9 +144,9 @@ class EventCreationService {
   /**
    * Check whether there have been form recurring configuration changes.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The stored event series entity.
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   The form state of an updated event series entity.
    *
    * @return bool
@@ -163,9 +163,9 @@ class EventCreationService {
   /**
    * Check whether there have been original recurring configuration changes.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The stored event series entity.
-   * @param Drupal\recurring_events\Entity\EventSeries $original
+   * @param \Drupal\recurring_events\Entity\EventSeries $original
    *   The original stored event series entity.
    *
    * @return bool
@@ -182,7 +182,7 @@ class EventCreationService {
   /**
    * Converts an EventSeries entity's recurring configuration to an array.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The stored event series entity.
    *
    * @return array
@@ -211,7 +211,7 @@ class EventCreationService {
   /**
    * Converts a form state object's recurring configuration to an array.
    *
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   The form state of an updated event series entity.
    *
    * @return array
@@ -298,17 +298,17 @@ class EventCreationService {
   /**
    * Build diff array between stored entity and form state.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The stored event series entity.
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface|null $form_state
    *   (Optional) The form state of an updated event series entity.
-   * @param Drupal\recurring_events\Entity\EventSeries $edited
+   * @param \Drupal\recurring_events\Entity\EventSeries|null $edited
    *   (Optional) The edited event series entity.
    *
    * @return array
    *   An array of differences.
    */
-  public function buildDiffArray(EventSeries $event, FormStateInterface $form_state = NULL, EventSeries $edited = NULL) {
+  public function buildDiffArray(EventSeries $event, ?FormStateInterface $form_state = NULL, ?EventSeries $edited = NULL) {
     $diff = [];
 
     $entity_config = $this->convertEntityConfigToArray($event);
@@ -397,7 +397,7 @@ class EventCreationService {
   /**
    * Clear out existing event instances..
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The event series entity.
    */
   public function clearEventInstances(EventSeries $event) {
@@ -527,11 +527,11 @@ class EventCreationService {
   /**
    * Create an event instance from an event series.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The stored event series entity.
-   * @param Drupal\Core\Datetime\DrupalDateTime $start_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $start_date
    *   The start date and time of the event.
-   * @param Drupal\Core\Datetime\DrupalDateTime $end_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $end_date
    *   The end date and time of the event.
    *
    * @return \Drupal\recurring_events\Entity\EventInstance
@@ -590,12 +590,13 @@ class EventCreationService {
   /**
    * Configure the default field inheritances for event instances.
    *
-   * @param Drupal\recurring_events\Entity\EventInstance $instance
+   * @param \Drupal\recurring_events\Entity\EventInstance $instance
    *   The event instance.
-   * @param int $series_id
-   *   The event series entity ID.
+   * @param int|null $series_id
+   *   Optional event series entity ID. If omitted, the event series ID will be
+   *   taken from the instance.
    */
-  public function configureDefaultInheritances(EventInstance $instance, int $series_id = NULL) {
+  public function configureDefaultInheritances(EventInstance $instance, ?int $series_id = NULL) {
     if (is_null($series_id)) {
       $series_id = $instance->eventseries_id->target_id;
     }
@@ -636,9 +637,9 @@ class EventCreationService {
   /**
    * When adding a new field inheritance, add the default values for it.
    *
-   * @param Drupal\recurring_events\Entity\EventInstance $instance
+   * @param \Drupal\recurring_events\Entity\EventInstance $instance
    *   The event instance for which to configure default inheritance values.
-   * @param Drupal\field_inheritance\Entity\FieldInheritanceInterface $field_inheritance
+   * @param \Drupal\field_inheritance\Entity\FieldInheritanceInterface $field_inheritance
    *   The field inheritance being created or updated.
    */
   public function addNewDefaultInheritance(EventInstance $instance, FieldInheritanceInterface $field_inheritance) {
@@ -747,9 +748,9 @@ class EventCreationService {
   /**
    * Update instance status.
    *
-   * @param Drupal\recurring_events\Entity\EventInstance $instance
+   * @param \Drupal\recurring_events\Entity\EventInstance $instance
    *   The event instance for which to update the status.
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The event series entity.
    */
   public function updateInstanceStatus(EventInstance $instance, EventSeries $event) {
diff --git a/src/Form/EventInstanceDeleteForm.php b/src/Form/EventInstanceDeleteForm.php
index 9cbf719f8781d6817cdd38d303aaf25abbf72215..e0532a80ef7868bba531fbeb4efcaf8af4a566da 100644
--- a/src/Form/EventInstanceDeleteForm.php
+++ b/src/Form/EventInstanceDeleteForm.php
@@ -45,16 +45,16 @@ class EventInstanceDeleteForm extends ContentEntityDeleteForm {
    *
    * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
    *   The entity repository service.
-   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
+   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface|null $entity_type_bundle_info
    *   The entity type bundle info interface.
-   * @param \Drupal\Component\Datetime\TimeInterface $time
+   * @param \Drupal\Component\Datetime\TimeInterface|null $time
    *   The time interface.
    * @param \Drupal\Core\Messenger\Messenger $messenger
    *   The messenger service.
    * @param \Drupal\Core\Datetime\DateFormatter $date_formatter
    *   The date formatter service.
    */
-  public function __construct(EntityRepositoryInterface $entity_repository, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL, Messenger $messenger, DateFormatter $date_formatter) {
+  public function __construct(EntityRepositoryInterface $entity_repository, ?EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, ?TimeInterface $time = NULL, Messenger $messenger, DateFormatter $date_formatter) {
     parent::__construct($entity_repository, $entity_type_bundle_info, $time);
     $this->messenger = $messenger;
     $this->dateFormatter = $date_formatter;
diff --git a/src/Form/EventInstanceSettingsForm.php b/src/Form/EventInstanceSettingsForm.php
index 6fb15a9dfc8519f12c99433142f7114aa31ec786..c3971f2b4322f18ebff53195c621866a15a34feb 100644
--- a/src/Form/EventInstanceSettingsForm.php
+++ b/src/Form/EventInstanceSettingsForm.php
@@ -36,7 +36,7 @@ class EventInstanceSettingsForm extends ConfigFormBase {
    *
    * @param array $form
    *   An associative array containing the structure of the form.
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   An associative array containing the current state of the form.
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
@@ -53,7 +53,7 @@ class EventInstanceSettingsForm extends ConfigFormBase {
    *
    * @param array $form
    *   An associative array containing the structure of the form.
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   An associative array containing the current state of the form.
    *
    * @return array
diff --git a/src/Form/EventSeriesDeleteForm.php b/src/Form/EventSeriesDeleteForm.php
index 446cd9c8367ce574764f4e20e70f7bf2064f599d..7da17ca322ae6fd2ed2126228e22fb895f4dc895 100644
--- a/src/Form/EventSeriesDeleteForm.php
+++ b/src/Form/EventSeriesDeleteForm.php
@@ -67,9 +67,9 @@ class EventSeriesDeleteForm extends ContentEntityDeleteForm {
    *
    * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
    *   The entity repository service.
-   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
+   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface|null $entity_type_bundle_info
    *   The entity type bundle info interface.
-   * @param \Drupal\Component\Datetime\TimeInterface $time
+   * @param \Drupal\Component\Datetime\TimeInterface|null $time
    *   The time interface.
    * @param \Drupal\Core\Messenger\Messenger $messenger
    *   The messenger service.
@@ -78,7 +78,7 @@ class EventSeriesDeleteForm extends ContentEntityDeleteForm {
    * @param \Drupal\Core\Config\ConfigFactory $config
    *   The config factory service.
    */
-  public function __construct(EntityRepositoryInterface $entity_repository, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL, Messenger $messenger, Renderer $renderer, ConfigFactory $config) {
+  public function __construct(EntityRepositoryInterface $entity_repository, ?EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, ?TimeInterface $time = NULL, Messenger $messenger, Renderer $renderer, ConfigFactory $config) {
     $this->messenger = $messenger;
     $this->renderer = $renderer;
     $this->config = $config;
diff --git a/src/Form/EventSeriesForm.php b/src/Form/EventSeriesForm.php
index 0e32de665bdca10f6c5c0e44214d05c8912d00cb..0e5ec1373ebdffe60d3b6bdfceb8cf700565c628 100644
--- a/src/Form/EventSeriesForm.php
+++ b/src/Form/EventSeriesForm.php
@@ -141,18 +141,31 @@ class EventSeriesForm extends ContentEntityForm {
    *   The field type plugin manager.
    * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
    *   The entity repository interface.
-   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
+   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface|null $entity_type_bundle_info
    *   The entity type bundle info interface.
-   * @param \Drupal\Component\Datetime\TimeInterface $time
+   * @param \Drupal\Component\Datetime\TimeInterface|null $time
    *   The time interface.
-   * @param \Drupal\Core\Session\AccountProxyInterface $current_user
+   * @param \Drupal\Core\Session\AccountProxyInterface|null $current_user
    *   The current user.
-   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface|null $module_handler
    *   The module handler service.
-   * @param \Drupal\Core\Config\ConfigFactory $config_factory
+   * @param \Drupal\Core\Config\ConfigFactory|null $config_factory
    *   The config factory.
    */
-  public function __construct(EventCreationService $creation_service, EntityStorageInterface $storage, Messenger $messenger, DateFormatter $date_formatter, EntityFieldManager $entity_field_manager, FieldTypePluginManager $field_type_plugin_manager, EntityRepositoryInterface $entity_repository, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL, AccountProxyInterface $current_user = NULL, ModuleHandlerInterface $module_handler = NULL, ConfigFactory $config_factory = NULL) {
+  public function __construct(
+    EventCreationService $creation_service,
+    EntityStorageInterface $storage,
+    Messenger $messenger,
+    DateFormatter $date_formatter,
+    EntityFieldManager $entity_field_manager,
+    FieldTypePluginManager $field_type_plugin_manager,
+    EntityRepositoryInterface $entity_repository,
+    ?EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL,
+    ?TimeInterface $time = NULL,
+    ?AccountProxyInterface $current_user = NULL,
+    ?ModuleHandlerInterface $module_handler = NULL,
+    ?ConfigFactory $config_factory = NULL,
+  ) {
     $this->creationService = $creation_service;
     $this->storage = $storage;
     $this->messenger = $messenger;
diff --git a/src/Form/EventSeriesSettingsForm.php b/src/Form/EventSeriesSettingsForm.php
index 600aa897006db38fcf27ea432f26782dbc6ee1e0..47da1b26f27893a7df12f29f3c07bb945f2ac1d3 100644
--- a/src/Form/EventSeriesSettingsForm.php
+++ b/src/Form/EventSeriesSettingsForm.php
@@ -76,7 +76,7 @@ class EventSeriesSettingsForm extends ConfigFormBase {
    *
    * @param array $form
    *   An associative array containing the structure of the form.
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   An associative array containing the current state of the form.
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
@@ -106,7 +106,7 @@ class EventSeriesSettingsForm extends ConfigFormBase {
    *
    * @param array $form
    *   An associative array containing the structure of the form.
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   An associative array containing the current state of the form.
    *
    * @return array
diff --git a/src/Plugin/Field/FieldType/ConsecutiveRecurringDate.php b/src/Plugin/Field/FieldType/ConsecutiveRecurringDate.php
index d8129dcb19ff8df5709c5675cda3b2a328be7419..9ebe678502cab3e2047439630d70799c3054304f 100644
--- a/src/Plugin/Field/FieldType/ConsecutiveRecurringDate.php
+++ b/src/Plugin/Field/FieldType/ConsecutiveRecurringDate.php
@@ -290,9 +290,9 @@ class ConsecutiveRecurringDate extends DateRangeItem implements RecurringEventsF
   /**
    * Find all the daily date occurrences between two dates.
    *
-   * @param Drupal\Core\Datetime\DrupalDateTime $start_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $start_date
    *   The start date.
-   * @param Drupal\Core\Datetime\DrupalDateTime $end_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $end_date
    *   The end date.
    * @param bool $count_only
    *   Whether to only return a count.
@@ -342,7 +342,7 @@ class ConsecutiveRecurringDate extends DateRangeItem implements RecurringEventsF
   /**
    * Find all the time slots between two times of a specific day.
    *
-   * @param Drupal\Core\Datetime\DrupalDateTime $date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $date
    *   The date.
    * @param array $form_data
    *   The form data used to find the time slots.
diff --git a/src/Plugin/Field/FieldType/DailyRecurringDate.php b/src/Plugin/Field/FieldType/DailyRecurringDate.php
index 5f8b01e2428a1839ea76850ab41cc6a005085f13..dc3854b11a74fcafc0c01ca86df295f016a05b20 100644
--- a/src/Plugin/Field/FieldType/DailyRecurringDate.php
+++ b/src/Plugin/Field/FieldType/DailyRecurringDate.php
@@ -258,9 +258,9 @@ class DailyRecurringDate extends DateRangeItem implements RecurringEventsFieldTy
   /**
    * Find all the daily date occurrences between two dates.
    *
-   * @param Drupal\Core\Datetime\DrupalDateTime $start_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $start_date
    *   The start date.
-   * @param Drupal\Core\Datetime\DrupalDateTime $end_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $end_date
    *   The end date.
    *
    * @return array
diff --git a/src/Plugin/Field/FieldType/WeeklyRecurringDate.php b/src/Plugin/Field/FieldType/WeeklyRecurringDate.php
index c3c5be200d6ba89ef1e43dedb40e799d1bcef436..a41ff0be6fda5d41d2a6baaca8dec9b2e5db6add 100644
--- a/src/Plugin/Field/FieldType/WeeklyRecurringDate.php
+++ b/src/Plugin/Field/FieldType/WeeklyRecurringDate.php
@@ -197,9 +197,9 @@ class WeeklyRecurringDate extends DailyRecurringDate implements RecurringEventsF
    *
    * @param string $weekday
    *   The name of the day of the week.
-   * @param Drupal\Core\Datetime\DrupalDateTime $start_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $start_date
    *   The start date.
-   * @param Drupal\Core\Datetime\DrupalDateTime $end_date
+   * @param \Drupal\Core\Datetime\DrupalDateTime $end_date
    *   The end date.
    *
    * @return array
diff --git a/src/Plugin/migrate/destination/EntityEventSeries.php b/src/Plugin/migrate/destination/EntityEventSeries.php
index 3df749c07686b088854158b498368aa9ded9662b..de6184774ca5b76cb2b7f38dfde6f4d2c2ac8515 100644
--- a/src/Plugin/migrate/destination/EntityEventSeries.php
+++ b/src/Plugin/migrate/destination/EntityEventSeries.php
@@ -2,12 +2,12 @@
 
 namespace Drupal\recurring_events\Plugin\migrate\destination;
 
-use Drupal\migrate\Plugin\migrate\destination\EntityContentBase;
 use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\migrate\Plugin\migrate\destination\EntityContentBase;
 use Drupal\migrate\Row;
 use Drupal\recurring_events\Entity\EventSeries;
-use Drupal\recurring_events\Plugin\migrate\process\RecurringDate;
 use Drupal\recurring_events\Plugin\migrate\process\RRuleHelper;
+use Drupal\recurring_events\Plugin\migrate\process\RecurringDate;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -85,7 +85,7 @@ class EntityEventSeries extends EntityContentBase {
   /**
    * {@inheritdoc}
    */
-  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, ?MigrationInterface $migration = NULL) {
     $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition, $migration);
     $instance->moduleHandler = $container->get('module_handler');
     return $instance;
diff --git a/src/Plugin/views/filter/TaxonomyIndexTidEventSeriesDepth.php b/src/Plugin/views/filter/TaxonomyIndexTidEventSeriesDepth.php
index 6203617305b627ffc34d293e6f39fd80ce7a81b1..8c383669951a5d9c743978e4608efd37e05d5398 100644
--- a/src/Plugin/views/filter/TaxonomyIndexTidEventSeriesDepth.php
+++ b/src/Plugin/views/filter/TaxonomyIndexTidEventSeriesDepth.php
@@ -74,16 +74,16 @@ class TaxonomyIndexTidEventSeriesDepth extends TaxonomyIndexTid {
    *   The vocabulary storage.
    * @param \Drupal\taxonomy\TermStorageInterface $term_storage
    *   The term storage.
-   * @param \Drupal\Core\Session\AccountInterface $current_user
+   * @param \Drupal\Core\Session\AccountInterface|null $current_user
    *   The current user.
-   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
+   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface|null $entity_type_bundle_info
    *   The entity type bundle service.
-   * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
+   * @param \Drupal\Core\Entity\EntityFieldManagerInterface|null $entity_field_manager
    *   The entity field manager.
    * @param \Drupal\Core\Database\Connection $database
    *   The database service.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, VocabularyStorageInterface $vocabulary_storage, TermStorageInterface $term_storage, AccountInterface $current_user = NULL, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, EntityFieldManagerInterface $entity_field_manager = NULL, Connection $database) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, VocabularyStorageInterface $vocabulary_storage, TermStorageInterface $term_storage, ?AccountInterface $current_user = NULL, ?EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, ?EntityFieldManagerInterface $entity_field_manager = NULL, Connection $database) {
     parent::__construct($configuration, $plugin_id, $plugin_definition, $vocabulary_storage, $term_storage, $current_user);
     $this->entityTypeBundleInfo = $entity_type_bundle_info;
     $this->entityFieldManager = $entity_field_manager;
diff --git a/src/RecurringEventsFieldTypeInterface.php b/src/RecurringEventsFieldTypeInterface.php
index 43fbb0abc6f462e83797aebaee7b23def24e048d..2abace41f1d2b132d009948489aed22ed4d1ea3e 100644
--- a/src/RecurringEventsFieldTypeInterface.php
+++ b/src/RecurringEventsFieldTypeInterface.php
@@ -13,7 +13,7 @@ interface RecurringEventsFieldTypeInterface {
   /**
    * Converts an EventSeries entity's recurring configuration to an array.
    *
-   * @param Drupal\recurring_events\Entity\EventSeries $event
+   * @param \Drupal\recurring_events\Entity\EventSeries $event
    *   The stored event series entity.
    *
    * @return array
@@ -24,7 +24,7 @@ interface RecurringEventsFieldTypeInterface {
   /**
    * Converts a form state object's recurring configuration to an array.
    *
-   * @param Drupal\Core\Form\FormStateInterface $form_state
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   The form state of an updated event series entity.
    *
    * @return array
diff --git a/tests/src/Unit/Plugin/migrate/destination/EntityEventSeriesTest.php b/tests/src/Unit/Plugin/migrate/destination/EntityEventSeriesTest.php
index 23e0c0e08b9bdd4c5b29a5011abac707a2da341a..c2fefc0854e4d64ca157dc0b769e310c0a7213be 100644
--- a/tests/src/Unit/Plugin/migrate/destination/EntityEventSeriesTest.php
+++ b/tests/src/Unit/Plugin/migrate/destination/EntityEventSeriesTest.php
@@ -8,9 +8,9 @@ use Drupal\Core\Field\FieldTypePluginManagerInterface;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\Session\AccountSwitcherInterface;
+use Drupal\Tests\migrate\Unit\Plugin\migrate\destination\EntityTestBase;
 use Drupal\migrate\Row;
 use Drupal\recurring_events\Plugin\migrate\destination\EntityEventSeries;
-use Drupal\Tests\migrate\Unit\Plugin\migrate\destination\EntityTestBase;
 use Prophecy\Argument;
 
 /**
diff --git a/tests/src/Unit/Plugin/migrate/process/RecurringDateTest.php b/tests/src/Unit/Plugin/migrate/process/RecurringDateTest.php
index bd6a403ac69d31e4706c592282c5b6520fcd277a..6546344ae50d7ee9607078bcdd39edbeab4203aa 100644
--- a/tests/src/Unit/Plugin/migrate/process/RecurringDateTest.php
+++ b/tests/src/Unit/Plugin/migrate/process/RecurringDateTest.php
@@ -7,8 +7,8 @@ use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\Core\StringTranslation\TranslationInterface;
-use Drupal\recurring_events\Plugin\migrate\process\RecurringDate;
 use Drupal\Tests\migrate\Unit\process\MigrateProcessTestCase;
+use Drupal\recurring_events\Plugin\migrate\process\RecurringDate;
 use Prophecy\Argument;
 
 /**