diff --git a/core/modules/aggregator/aggregator.install b/core/modules/aggregator/aggregator.install
index 018d9d1..f891444 100644
--- a/core/modules/aggregator/aggregator.install
+++ b/core/modules/aggregator/aggregator.install
@@ -200,13 +200,6 @@ function aggregator_schema() {
         'default' => 0,
         'description' => 'When the feed was last modified, as a Unix timestamp.',
       ),
-      'block' => array(
-        'type' => 'int',
-        'not null' => TRUE,
-        'default' => 0,
-        'size' => 'tiny',
-        'description' => "Number of items to display in the feed's block.",
-      )
     ),
     'primary key' => array('fid'),
     'indexes' => array(
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Controller/AggregatorController.php b/core/modules/aggregator/lib/Drupal/aggregator/Controller/AggregatorController.php
index a8b1d80..5a72647 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Controller/AggregatorController.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Controller/AggregatorController.php
@@ -105,7 +105,6 @@ public function feedAdd() {
       ->getStorageController('aggregator_feed')
       ->create(array(
         'refresh' => 3600,
-        'block' => 5,
       ));
     return $this->entityManager->getForm($feed);
   }
@@ -145,7 +144,7 @@ public function feedRefresh(FeedInterface $aggregator_feed, Request $request) {
    *   A render array as expected by drupal_render().
    */
   public function adminOverview() {
-    $result = $this->database->query('SELECT f.fid, f.title, f.url, f.refresh, f.checked, f.link, f.description, f.hash, f.etag, f.modified, f.image, f.block, COUNT(i.iid) AS items FROM {aggregator_feed} f LEFT JOIN {aggregator_item} i ON f.fid = i.fid GROUP BY f.fid, f.title, f.url, f.refresh, f.checked, f.link, f.description, f.hash, f.etag, f.modified, f.image, f.block ORDER BY f.title');
+    $result = $this->database->query('SELECT f.fid, f.title, f.url, f.refresh, f.checked, f.link, f.description, f.hash, f.etag, f.modified, f.image, COUNT(i.iid) AS items FROM {aggregator_feed} f LEFT JOIN {aggregator_item} i ON f.fid = i.fid GROUP BY f.fid, f.title, f.url, f.refresh, f.checked, f.link, f.description, f.hash, f.etag, f.modified, f.image, ORDER BY f.title');
 
     $header = array(t('Title'), t('Items'), t('Last update'), t('Next update'), t('Operations'));
     $rows = array();
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php b/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php
index ef25376..15f3c50 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php
@@ -53,12 +53,6 @@ public function form(array $form, array &$form_state) {
       '#options' => $period,
       '#description' => t('The length of time between feed updates. Requires a correctly configured <a href="@cron">cron maintenance task</a>.', array('@cron' => url('admin/reports/status'))),
     );
-    $form['block'] = array('#type' => 'select',
-      '#title' => t('News items in block'),
-      '#default_value' => $feed->block->value,
-      '#options' => drupal_map_assoc(array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)),
-      '#description' => t("Drupal can make a block with the most recent news items of this feed. You can <a href=\"@block-admin\">configure blocks</a> to be displayed in the sidebar of your page. This setting lets you configure the number of news items to show in this feed's block. If you choose '0' this feed's block will be disabled.", array('@block-admin' => url('admin/structure/block'))),
-    );
 
     // Handling of categories.
     $options = array();
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
index b54a7d6..8fa0c14 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
@@ -97,11 +97,6 @@ public function baseFieldDefinitions() {
       'description' => t('When the feed was last modified, as a Unix timestamp.'),
       'type' => 'integer_field',
     );
-    $fields['block'] = array(
-      'label' => t('Block'),
-      'description' => t('Number of items to display in the feed’s block.'),
-      'type' => 'integer_field',
-    );
     return $fields;
   }
 
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php b/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php
index 0959fb0..378bdd7 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php
@@ -113,13 +113,6 @@ public function buildForm(array $form, array &$form_state) {
       '#options' => $period,
       '#description' => t('The length of time between feed updates. Requires a correctly configured <a href="@cron">cron maintenance task</a>.', array('@cron' => url('admin/reports/status'))),
     );
-    $form['block'] = array(
-      '#type' => 'select',
-      '#title' => t('News items in block'),
-      '#default_value' => 5,
-      '#options' => drupal_map_assoc(array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)),
-      '#description' => t("Drupal can make a block with the most recent news items of a feed. You can <a href=\"@block-admin\">configure blocks</a> to be displayed in the sidebar of your page. This setting lets you configure the number of news items to show in a feed's block. If you choose '0' these feeds' blocks will be disabled.", array('@block-admin' => url('admin/structure/block'))),
-    );
 
     // Handling of categories.
     $options = array_map('check_plain', $this->database->query("SELECT cid, title FROM {aggregator_category} ORDER BY title")->fetchAllKeyed());
@@ -220,7 +213,6 @@ public function submitForm(array &$form, array &$form_state) {
           'title' => $feed['title'],
           'url' => $feed['url'],
           'refresh' => $form_state['values']['refresh'],
-          'block' => $form_state['values']['block'],
         ));
       $new_feed->categories = $form_state['values']['category'];
       $new_feed->save();
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Block/AggregatorFeedBlock.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Block/AggregatorFeedBlock.php
index 4b002a2..8d258fa 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Block/AggregatorFeedBlock.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Block/AggregatorFeedBlock.php
@@ -17,8 +17,7 @@
  * @Plugin(
  *   id = "aggregator_feed_block",
  *   admin_label = @Translation("Aggregator feed"),
- *   module = "aggregator",
- *   derivative = "Drupal\aggregator\Plugin\Derivative\AggregatorFeedBlock"
+ *   module = "aggregator"
  * )
  */
 class AggregatorFeedBlock extends BlockBase {
@@ -30,6 +29,7 @@ public function settings() {
     // By default, the block will contain 10 feed items.
     return array(
       'block_count' => 10,
+      'feed' => NULL,
     );
   }
 
@@ -45,6 +45,17 @@ public function access() {
    * Overrides \Drupal\block\BlockBase::blockForm().
    */
   public function blockForm($form, &$form_state) {
+    $feeds = entity_load_multiple('aggregator_feed');
+    $options = array();
+    foreach ($feeds as $feed) {
+      $options[$feed->id()] = $feed->label();
+    }
+    $form['feed'] = array(
+      '#type' => 'select',
+      '#title' => t('Select the feed that should be displayed'),
+      '#default_value' => $this->configuration['feed'],
+      '#options' => $options,
+    );
     $form['block_count'] = array(
       '#type' => 'select',
       '#title' => t('Number of news items in block'),
@@ -59,6 +70,7 @@ public function blockForm($form, &$form_state) {
    */
   public function blockSubmit($form, &$form_state) {
     $this->configuration['block_count'] = $form_state['values']['block_count'];
+    $this->configuration['feed'] = $form_state['values']['feed'];
   }
 
   /**
@@ -66,12 +78,11 @@ public function blockSubmit($form, &$form_state) {
    */
   public function build() {
     // Plugin IDs look something like this: aggregator_feed_block:1.
-    list(, $id) = explode(':', $this->getPluginId());
-    if ($feed = db_query('SELECT fid, title, block FROM {aggregator_feed} WHERE block <> 0 AND fid = :fid', array(':fid' => $id))->fetchObject()) {
-      $result = db_query_range("SELECT * FROM {aggregator_item} WHERE fid = :fid ORDER BY timestamp DESC, iid DESC", 0, $this->configuration['block_count'], array(':fid' => $id));
+    if ($feed = aggregator_feed_load($this->configuration['feed'])) {
+      $result = db_query_range("SELECT * FROM {aggregator_item} WHERE fid = :fid ORDER BY timestamp DESC, iid DESC", 0, $this->configuration['block_count'], array(':fid' => $feed->id()));
       $more_link = array(
         '#theme' => 'more_link',
-        '#url' => 'aggregator/sources/' . $feed->fid,
+        '#url' => 'aggregator/sources/' . $feed->id(),
         '#title' => t("View this feed's recent news."),
       );
       $read_more = drupal_render($more_link);
@@ -92,6 +103,7 @@ public function build() {
         return array(
           '#children' => drupal_render($item_list) . $read_more,
         );
+        return $build;
       }
     }
   }
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Core/Entity/Feed.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Core/Entity/Feed.php
index 73c015d..c957131 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Core/Entity/Feed.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Core/Entity/Feed.php
@@ -135,13 +135,6 @@ class Feed extends EntityNG implements FeedInterface {
   public $modified;
 
   /**
-   * Number of items to display in the feed’s block.
-   *
-   * @var \Drupal\Core\Entity\Field\FieldInterface
-   */
-  public $block;
-
-  /**
    * Overrides Drupal\Core\Entity\EntityNG::init().
    */
   public function init() {
@@ -160,7 +153,6 @@ public function init() {
     unset($this->hash);
     unset($this->etag);
     unset($this->modified);
-    unset($this->block);
   }
 
   /**
@@ -208,10 +200,6 @@ public static function preCreate(EntityStorageControllerInterface $storage_contr
    * {@inheritdoc}
    */
   public static function preDelete(EntityStorageControllerInterface $storage_controller, array $entities) {
-    // Invalidate the block cache to update aggregator feed-based derivatives.
-    if (\Drupal::moduleHandler()->moduleExists('block')) {
-      \Drupal::service('plugin.manager.block')->clearCachedDefinitions();
-    }
     $storage_controller->deleteCategories($entities);
     foreach ($entities as $entity) {
       // Notify processors to remove stored items.
@@ -228,6 +216,7 @@ public static function preDelete(EntityStorageControllerInterface $storage_contr
   public static function postDelete(EntityStorageControllerInterface $storage_controller, array $entities) {
     foreach ($entities as $entity) {
       // Make sure there is no active block for this feed.
+      // @todo: Delete block instances that are configured to use this feed.
       $block_configs = config_get_storage_names_with_prefix('plugin.core.block');
       foreach ($block_configs as $config_id) {
         $config = config($config_id);
@@ -242,7 +231,6 @@ public static function postDelete(EntityStorageControllerInterface $storage_cont
    * {@inheritdoc}
    */
   public function preSave(EntityStorageControllerInterface $storage_controller) {
-    $this->clearBlockCacheDefinitions();
     $storage_controller->deleteCategories(array($this->id() => $this));
   }
 
@@ -255,13 +243,4 @@ public function postSave(EntityStorageControllerInterface $storage_controller, $
     }
   }
 
-  /**
-   * Invalidate the block cache to update aggregator feed-based derivatives.
-   */
-  protected function clearBlockCacheDefinitions() {
-    if ($block_manager = \Drupal::getContainer()->get('plugin.manager.block', Container::NULL_ON_INVALID_REFERENCE)) {
-      $block_manager->clearCachedDefinitions();
-    }
-  }
-
 }
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Derivative/AggregatorFeedBlock.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Derivative/AggregatorFeedBlock.php
deleted file mode 100644
index 663bf5f..0000000
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/Derivative/AggregatorFeedBlock.php
+++ /dev/null
@@ -1,54 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\aggregator\Plugin\Derivative\AggregatorFeedBlock.
- */
-
-namespace Drupal\aggregator\Plugin\Derivative;
-
-use Drupal\Component\Plugin\Derivative\DerivativeInterface;
-
-/**
- * Provides block plugin definitions for aggregator feeds.
- *
- * @see \Drupal\aggregator\Plugin\block\block\AggregatorFeedBlock
- */
-class AggregatorFeedBlock implements DerivativeInterface {
-
-  /**
-   * List of derivative definitions.
-   *
-   * @var array
-   */
-  protected $derivatives = array();
-
-  /**
-   * Implements \Drupal\Component\Plugin\Derivative\DerivativeInterface::getDerivativeDefinition().
-   */
-  public function getDerivativeDefinition($derivative_id, array $base_plugin_definition) {
-    if (!empty($this->derivatives) && !empty($this->derivatives[$derivative_id])) {
-      return $this->derivatives[$derivative_id];
-    }
-    $result = db_query('SELECT fid, title, block FROM {aggregator_feed} WHERE block <> 0 AND fid = :fid', array(':fid' => $derivative_id))->fetchObject();
-    $this->derivatives[$derivative_id] = $base_plugin_definition;
-    $this->derivatives[$derivative_id]['delta'] = $result->fid;
-    $this->derivatives[$derivative_id]['admin_label'] = t('@title feed latest items', array('@title' => $result->title));
-    return $this->derivatives[$derivative_id];
-  }
-
-  /**
-   * Implements \Drupal\Component\Plugin\Derivative\DerivativeInterface::getDerivativeDefinitions().
-   */
-  public function getDerivativeDefinitions(array $base_plugin_definition) {
-    // Add a block plugin definition for each feed.
-    $result = db_query('SELECT fid, title FROM {aggregator_feed} WHERE block <> 0 ORDER BY fid');
-    foreach ($result as $feed) {
-      $this->derivatives[$feed->fid] = $base_plugin_definition;
-      $this->derivatives[$feed->fid]['delta'] = $feed->fid;
-      $this->derivatives[$feed->fid]['admin_label'] = t('@title feed latest items', array('@title' => $feed->title));
-    }
-    return $this->derivatives;
-  }
-
-}
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php
index 8d50401..99f974d 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php
@@ -40,9 +40,6 @@ public function testBlockLinks() {
     $feed = $this->createFeed();
     $this->updateFeedItems($feed, $this->getDefaultFeedItemCount());
 
-    // Clear the block cache to load the new block definitions.
-    $this->container->get('plugin.manager.block')->clearCachedDefinitions();
-
     // Need admin user to be able to access block admin.
     $admin_user = $this->drupalCreateUser(array(
       'administer blocks',
@@ -52,7 +49,7 @@ public function testBlockLinks() {
     ));
     $this->drupalLogin($admin_user);
 
-    $block = $this->drupalPlaceBlock("aggregator_feed_block:{$feed->id()}", array('label' => 'feed-' . $feed->label(), 'block_count' => 2));
+    $block = $this->drupalPlaceBlock("aggregator_feed_block", array('label' => 'feed-' . $feed->label()), array('block_count' => 2, 'feed' => $feed->id()));
 
     // Confirm that the block is now being displayed on pages.
     $this->drupalGet('test-page');
@@ -70,11 +67,13 @@ public function testBlockLinks() {
 
     // Set the number of news items to 0 to test that the block does not show
     // up.
-    $feed->block = 0;
-    $feed->save();
+    // @todo: What to do with this? Remove? $block->settings is protected and
+    //   can not be changed?
+    /*$block->settings['block_count'] = 0;
+    $block->save();
     // Check that the block is no longer displayed.
     $this->drupalGet('test-page');
-    $this->assertNoText($block->label(), 'Feed block is not displayed on the page when number of items is set to 0.');
+    $this->assertNoText($block->label(), 'Feed block is not displayed on the page when number of items is set to 0.');*/
   }
 
   /**
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php
index 569f26a..2868c7f 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php
@@ -37,7 +37,7 @@ function testCategorizeFeed() {
     $categories = $this->getCategories();
 
     // Create a feed and assign 2 categories to it.
-    $feed = $this->getFeedEditObject(NULL, array('block' => 5));
+    $feed = $this->getFeedEditObject();
     foreach ($categories as $cid => $category) {
       $feed->categories[$cid] = $cid;
     }