jsonapi.module                            | 16 ----------------
 src/JsonapiServiceProvider.php            | 11 -----------
 tests/src/Functional/CommentTest.php      | 14 ++------------
 tests/src/Functional/MediaTest.php        | 13 +------------
 tests/src/Functional/ResourceTestBase.php |  4 ----
 5 files changed, 3 insertions(+), 55 deletions(-)

diff --git a/jsonapi.module b/jsonapi.module
index 1201a3f..7051f4a 100644
--- a/jsonapi.module
+++ b/jsonapi.module
@@ -32,22 +32,6 @@ function jsonapi_help($route_name, RouteMatchInterface $route_match) {
 }
 
 /**
- * Implements hook_entity_bundle_field_info().
- */
-function jsonapi_entity_bundle_field_info(EntityTypeInterface $entity_type, $bundle, array $base_field_definitions) {
-  $fields = [];
-
-  if (floatval(\Drupal::VERSION) < 8.6 && $entity_type->id() == 'taxonomy_term') {
-    // Only terms in the same bundle can be a parent.
-    $fields['parent'] = clone $base_field_definitions['parent'];
-    $fields['parent']->setSetting('handler_settings', ['target_bundles' => [$bundle]]);
-    return $fields;
-  }
-
-  return $fields;
-}
-
-/**
  * Implements hook_entity_bundle_create().
  */
 function jsonapi_entity_bundle_create() {
diff --git a/src/JsonapiServiceProvider.php b/src/JsonapiServiceProvider.php
index d04181e..79cef20 100644
--- a/src/JsonapiServiceProvider.php
+++ b/src/JsonapiServiceProvider.php
@@ -21,17 +21,6 @@ class JsonapiServiceProvider implements ServiceModifierInterface, ServiceProvide
    * {@inheritdoc}
    */
   public function alter(ContainerBuilder $container) {
-    // @todo Remove when we stop supporting Drupal 8.5.
-    if (floatval(\Drupal::VERSION) < 8.6) {
-      // Swap the cache service back.
-      $definition = $container->getDefinition('jsonapi.resource_type.repository');
-      $definition->setArgument(3, new Reference('cache.static'));
-      $container->setDefinition('jsonapi.resource_type.repository', $definition);
-
-      // Drop the new service definition.
-      $container->removeDefinition('cache.jsonapi_resource_types');
-    }
-
     if ($container->has('http_middleware.negotiation') && is_a($container->getDefinition('http_middleware.negotiation')
       ->getClass(), '\Drupal\Core\StackMiddleware\NegotiationMiddleware', TRUE)
     ) {
diff --git a/tests/src/Functional/CommentTest.php b/tests/src/Functional/CommentTest.php
index 683b26b..c2511ff 100644
--- a/tests/src/Functional/CommentTest.php
+++ b/tests/src/Functional/CommentTest.php
@@ -310,12 +310,7 @@ class CommentTest extends ResourceTestBase {
     // DX: 422 when missing 'entity_type' field.
     $request_options[RequestOptions::BODY] = Json::encode($remove_field($this->getPostDocument(), 'attributes', 'entity_type'));
     $response = $this->request('POST', $url, $request_options);
-    if (floatval(\Drupal::VERSION) >= 8.7) {
-      $this->assertResourceErrorResponse(422, 'entity_type: This value should not be null.', NULL, $response, '/data/attributes/entity_type');
-    }
-    else {
-      $this->assertResourceErrorResponse(500, 'The "" entity type does not exist.', $url, $response, FALSE);
-    }
+    $this->assertResourceErrorResponse(422, 'entity_type: This value should not be null.', NULL, $response, '/data/attributes/entity_type');
 
     // DX: 422 when missing 'entity_id' field.
     $request_options[RequestOptions::BODY] = Json::encode($remove_field($this->getPostDocument(), 'relationships', 'entity_id'));
@@ -331,12 +326,7 @@ class CommentTest extends ResourceTestBase {
     // DX: 422 when missing 'field_name' field.
     $request_options[RequestOptions::BODY] = Json::encode($remove_field($this->getPostDocument(), 'attributes', 'field_name'));
     $response = $this->request('POST', $url, $request_options);
-    if (floatval(\Drupal::VERSION) >= 8.7) {
-      $this->assertResourceErrorResponse(422, 'field_name: This value should not be null.', NULL, $response, '/data/attributes/field_name');
-    }
-    else {
-      $this->assertSame(500, $response->getStatusCode());
-    }
+    $this->assertResourceErrorResponse(422, 'field_name: This value should not be null.', NULL, $response, '/data/attributes/field_name');
   }
 
   /**
diff --git a/tests/src/Functional/MediaTest.php b/tests/src/Functional/MediaTest.php
index 1c86024..5a84540 100644
--- a/tests/src/Functional/MediaTest.php
+++ b/tests/src/Functional/MediaTest.php
@@ -134,7 +134,7 @@ class MediaTest extends ResourceTestBase {
     $thumbnail = File::load(3);
     $author = User::load($this->entity->getOwnerId());
     $self_url = Url::fromUri('base:/jsonapi/media/camelids/' . $this->entity->uuid())->setAbsolute()->toString(TRUE)->getGeneratedUrl();
-    $data = [
+    return [
       'jsonapi' => [
         'meta' => [
           'links' => [
@@ -232,12 +232,6 @@ class MediaTest extends ResourceTestBase {
         ],
       ],
     ];
-    // @todo Make this unconditional when JSON:API requires Drupal 8.6 or newer.
-    if (floatval(\Drupal::VERSION) < 8.6) {
-      $data['data']['relationships']['thumbnail']['data']['meta']['alt'] = 'Thumbnail';
-      $data['data']['relationships']['thumbnail']['data']['meta']['title'] = 'Llama';
-    }
-    return $data;
   }
 
   /**
@@ -324,11 +318,6 @@ class MediaTest extends ResourceTestBase {
           'height' => 180,
           'title' => NULL,
         ];
-        // @todo Make this unconditional when JSON:API requires Drupal 8.6 or newer.
-        if (floatval(\Drupal::VERSION) < 8.6) {
-          $data['meta']['alt'] = 'Thumbnail';
-          $data['meta']['title'] = 'Llama';
-        }
         return $data;
 
       case 'field_media_file':
diff --git a/tests/src/Functional/ResourceTestBase.php b/tests/src/Functional/ResourceTestBase.php
index ba80706..c77661a 100644
--- a/tests/src/Functional/ResourceTestBase.php
+++ b/tests/src/Functional/ResourceTestBase.php
@@ -1751,10 +1751,6 @@ abstract class ResourceTestBase extends BrowserTestBase {
         $detail = 'The current user is not allowed to view this relationship.';
         if (!$entity->access('view') && $entity->access('view label') && $access instanceof AccessResultReasonInterface && empty($access->getReason())) {
           $access->setReason("The user only has authorization for the 'view label' operation.");
-          // @todo Remove when we stop supporting Drupal 8.5.
-          if (floatval(\Drupal::VERSION) < 8.6 && $relationship_field_name === 'roles' && static::$entityTypeId === 'user' && $access->getCacheContexts() === ['user.permissions']) {
-            $access = $access->setReason('');
-          }
         }
         $via_link = Url::fromRoute(
           sprintf('jsonapi.%s.%s.related', $base_resource_identifier['type'], $relationship_field_name),