.../tests/Traits/ContentModerationTestTrait.php    | 91 ----------------------
 src/JsonapiServiceProvider.php                     |  6 --
 src/Routing/Routes.php                             |  5 --
 tests/src/Functional/FileUploadTest.php            |  3 -
 tests/src/Functional/ResourceTestBase.php          |  2 +-
 5 files changed, 1 insertion(+), 106 deletions(-)

diff --git a/src/BackwardCompatibility/tests/Traits/ContentModerationTestTrait.php b/src/BackwardCompatibility/tests/Traits/ContentModerationTestTrait.php
deleted file mode 100644
index 310bcfb..0000000
--- a/src/BackwardCompatibility/tests/Traits/ContentModerationTestTrait.php
+++ /dev/null
@@ -1,91 +0,0 @@
-<?php
-
-namespace Drupal\jsonapi\BackwardCompatibility\tests\Traits;
-
-use Drupal\workflows\Entity\Workflow;
-
-/**
- * Trait ContentModerationTestTraint.
- *
- * @see \Drupal\Tests\content_moderation\Traits\ContentModerationTestTrait
- * @todo Remove when JSON:API requires Drupal >=8.6
- */
-trait ContentModerationTestTrait {
-
-  /**
-   * Creates the editorial workflow.
-   *
-   * @return \Drupal\workflows\Entity\Workflow
-   *   The editorial workflow entity.
-   */
-  protected function createEditorialWorkflow() {
-    $workflow = Workflow::create([
-      'type' => 'content_moderation',
-      'id' => 'editorial',
-      'label' => 'Editorial',
-      'type_settings' => [
-        'states' => [
-          'archived' => [
-            'label' => 'Archived',
-            'weight' => 5,
-            'published' => FALSE,
-            'default_revision' => TRUE,
-          ],
-          'draft' => [
-            'label' => 'Draft',
-            'published' => FALSE,
-            'default_revision' => FALSE,
-            'weight' => -5,
-          ],
-          'published' => [
-            'label' => 'Published',
-            'published' => TRUE,
-            'default_revision' => TRUE,
-            'weight' => 0,
-          ],
-        ],
-        'transitions' => [
-          'archive' => [
-            'label' => 'Archive',
-            'from' => ['published'],
-            'to' => 'archived',
-            'weight' => 2,
-          ],
-          'archived_draft' => [
-            'label' => 'Restore to Draft',
-            'from' => ['archived'],
-            'to' => 'draft',
-            'weight' => 3,
-          ],
-          'archived_published' => [
-            'label' => 'Restore',
-            'from' => ['archived'],
-            'to' => 'published',
-            'weight' => 4,
-          ],
-          'create_new_draft' => [
-            'label' => 'Create New Draft',
-            'to' => 'draft',
-            'weight' => 0,
-            'from' => [
-              'draft',
-              'published',
-            ],
-          ],
-          'publish' => [
-            'label' => 'Publish',
-            'to' => 'published',
-            'weight' => 1,
-            'from' => [
-              'draft',
-              'published',
-            ],
-          ],
-        ],
-      ],
-    ]);
-    $workflow->save();
-    return $workflow;
-  }
-
-}
diff --git a/src/JsonapiServiceProvider.php b/src/JsonapiServiceProvider.php
index fe43787..4c6ba49 100644
--- a/src/JsonapiServiceProvider.php
+++ b/src/JsonapiServiceProvider.php
@@ -34,12 +34,6 @@ class JsonapiServiceProvider implements ServiceModifierInterface, ServiceProvide
           ['application/octet-stream'],
         ]);
     }
-
-    // @todo Remove this when JSON:API requires Drupal >=8.6, see https://www.drupal.org/node/1927648.
-    if (floatval(\Drupal::VERSION) < 8.6) {
-      $container->removeDefinition('jsonapi.file_upload');
-      $container->removeDefinition('file.uploader');
-    }
   }
 
   /**
diff --git a/src/Routing/Routes.php b/src/Routing/Routes.php
index 3ccfd29..230d6de 100644
--- a/src/Routing/Routes.php
+++ b/src/Routing/Routes.php
@@ -205,11 +205,6 @@ class Routes implements ContainerInjectionInterface {
    *   The route collection.
    */
   protected static function getFileUploadRoutesForResourceType(ResourceType $resource_type, $path_prefix) {
-    // @todo Remove this when JSON:API requires Drupal >=8.6, see https://www.drupal.org/node/1927648.
-    if (\Drupal::VERSION < 8.6) {
-      return new RouteCollection();
-    }
-
     $routes = new RouteCollection();
 
     // Internal resources have no routes; individual routes require locations.
diff --git a/tests/src/Functional/FileUploadTest.php b/tests/src/Functional/FileUploadTest.php
index 69e9a77..1c380aa 100644
--- a/tests/src/Functional/FileUploadTest.php
+++ b/tests/src/Functional/FileUploadTest.php
@@ -19,9 +19,6 @@ use Psr\Http\Message\ResponseInterface;
  * Tests binary data file upload route.
  *
  * @group jsonapi
- * @requires function Drupal\file\Plugin\rest\resource\FileUploadResource::post
- *
- * @todo Remove the "@requires" annotation when JSON:API requires Drupal >=8.6
  */
 class FileUploadTest extends ResourceTestBase {
 
diff --git a/tests/src/Functional/ResourceTestBase.php b/tests/src/Functional/ResourceTestBase.php
index 27bd797..0ee43ad 100644
--- a/tests/src/Functional/ResourceTestBase.php
+++ b/tests/src/Functional/ResourceTestBase.php
@@ -26,7 +26,6 @@ use Drupal\Core\TypedData\TypedDataInternalPropertiesHelper;
 use Drupal\Core\Url;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
-use Drupal\jsonapi\BackwardCompatibility\tests\Traits\ContentModerationTestTrait;
 use Drupal\jsonapi\JsonApiResource\LinkCollection;
 use Drupal\jsonapi\JsonApiResource\NullEntityCollection;
 use Drupal\jsonapi\JsonApiResource\Link;
@@ -35,6 +34,7 @@ use Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel;
 use Drupal\jsonapi\ResourceResponse;
 use Drupal\path\Plugin\Field\FieldType\PathItem;
 use Drupal\Tests\BrowserTestBase;
+use Drupal\Tests\content_moderation\Traits\ContentModerationTestTrait;
 use Drupal\user\Entity\Role;
 use Drupal\user\EntityOwnerInterface;
 use Drupal\user\RoleInterface;