diff --git a/search_api.install b/search_api.install
index e24736c..9b1883f 100644
--- a/search_api.install
+++ b/search_api.install
@@ -125,3 +125,42 @@ function search_api_requirements($phase) {
   }
   return array();
 }
+
+/**
+ * Adapts index config schema to remove an unnecessary layer for plugins.
+ */
+function search_api_update_8101() {
+  // This update function updates search indexes for the change from
+  // https://www.drupal.org/node/2656052.
+  $config_factory = \Drupal::configFactory();
+  $plugin_types = [
+    'processor',
+    'datasource',
+    'tracker',
+  ];
+
+  foreach ($config_factory->listAll('search_api.index.') as $index_id) {
+    $index = $config_factory->getEditable($index_id);
+    $changed = FALSE;
+
+    foreach ($plugin_types as $plugin_type) {
+      $property = $plugin_type . '_settings';
+      $plugins = $index->get($property);
+      foreach ($plugins as $id => $config) {
+        if (isset($config['plugin_id']) && isset($config['settings'])) {
+          $changed = TRUE;
+          $plugins[$id] = $config['settings'];
+        }
+      }
+      $index->set($property, $plugins);
+    }
+
+    if ($changed) {
+      // Mark the resulting configuration as trusted data. This avoids issues
+      // with future schema changes.
+      $index->save(TRUE);
+    }
+  }
+
+  return t('Index config schema updated.');
+}
diff --git a/tests/src/Kernel/ContentEntityDatasourceTest.php b/tests/src/Kernel/ContentEntityDatasourceTest.php
index 34146bd..3a1ad6a 100644
--- a/tests/src/Kernel/ContentEntityDatasourceTest.php
+++ b/tests/src/Kernel/ContentEntityDatasourceTest.php
@@ -80,16 +80,10 @@ public function setUp() {
       'id' => 'test_index',
       'status' => FALSE,
       'datasource_settings' => array(
-        'entity:' . $this->testEntityTypeId => array(
-          'plugin_id' => 'entity:' . $this->testEntityTypeId,
-          'settings' => array(),
-        ),
+        'entity:' . $this->testEntityTypeId => array(),
       ),
       'tracker_settings' => array(
-        'default' => array(
-          'plugin_id' => 'default',
-          'settings' => array(),
-        ),
+        'default' => array(),
       ),
     ));
     $this->datasource = $this->index->getDatasource('entity:' . $this->testEntityTypeId);
diff --git a/tests/src/Kernel/FieldValuesExtractionTest.php b/tests/src/Kernel/FieldValuesExtractionTest.php
index 8ebf023..a8e786b 100644
--- a/tests/src/Kernel/FieldValuesExtractionTest.php
+++ b/tests/src/Kernel/FieldValuesExtractionTest.php
@@ -120,10 +120,7 @@ public function setUp() {
         ),
       ),
       'datasource_settings' => array(
-        'entity:entity_test_mulrev_changed' => array(
-          'plugin_id' => 'entity:entity_test_mulrev_changed',
-          'settings' => array(),
-        ),
+        'entity:entity_test_mulrev_changed' => array(),
       ),
     ));