diff --git a/core/modules/migrate_drupal/src/MigrationState.php b/core/modules/migrate_drupal/src/MigrationState.php
index b44108a80cd..593b0c04185 100644
--- a/core/modules/migrate_drupal/src/MigrationState.php
+++ b/core/modules/migrate_drupal/src/MigrationState.php
@@ -155,21 +155,6 @@ class MigrationState {
    */
   protected $fieldPluginManager;
 
-  /**
-   * Source modules that will not be migrated determined using legacy method.
-   *
-   * @var array
-   */
-  protected $unmigratedSourceModules = [];
-
-  /**
-   * Source modules that will be migrated determined using legacy method, keyed
-   * by version.
-   *
-   * @var array
-   */
-  protected $migratedSourceModules = [];
-
   /**
    * An array of migration states declared for each source migration.
    *
@@ -323,25 +308,6 @@ class MigrationState {
       // source_modules are enabled so do the same here.
       if ($module['status']) {
         $source_module = $module['name'];
-        // If there is not a declared state for this source module then use the
-        // legacy method for determining the migration state.
-        if (!isset($this->stateBySource[$version][$source_module])) {
-          // No migrations found for this source module.
-          if (!empty($this->unmigratedSourceModules[$version]) && array_key_exists($source_module, $this->unmigratedSourceModules[$version])) {
-            $upgrade_state[static::NOT_FINISHED][$source_module] = '';
-            continue;
-          }
-          if (!empty($this->migratedSourceModules[$version]) && array_key_exists($source_module, $this->migratedSourceModules[$version])) {
-            @trigger_error(sprintf("Using migration plugin definitions to determine the migration state of the module '%s' is deprecated in Drupal 8.7. Add the module to a migrate_drupal.yml file. See https://www.drupal.org/node/2929443", $source_module), E_USER_DEPRECATED);
-            if (array_diff(array_keys($this->migratedSourceModules[$version][$source_module]), $this->enabledModules)) {
-              $upgrade_state[static::NOT_FINISHED][$source_module] = implode(', ', array_keys($this->migratedSourceModules[$version][$source_module]));
-              continue;
-            }
-            $upgrade_state[static::FINISHED][$source_module] = implode(', ', array_keys($this->migratedSourceModules[$version][$source_module]));
-          }
-          continue;
-        }
-
         $upgrade_state[$this->getSourceState($version, $source_module)][$source_module] = implode(', ', $this->getDestinationsForSource($version, $source_module));
       }
 
@@ -401,13 +367,6 @@ class MigrationState {
     foreach ($table_data as $source_module => $destination_module_info) {
       ksort($table_data[$source_module]);
     }
-    $tmp = array_diff_key($source_system_data['module'], $table_data);
-    foreach ($tmp as $source_module => $module_data) {
-      if ($module_data['status']) {
-        $this->unmigratedSourceModules[$version][$source_module] = $module_data;
-      }
-    }
-    $this->migratedSourceModules[$version] = $table_data;
     $this->discoveredBySource[$version] = array_map('array_unique', $discovered_upgrade_paths);
   }
 
@@ -458,6 +417,10 @@ class MigrationState {
       // No discovered or declared state.
       return MigrationState::NOT_FINISHED;
     }
+    if (!isset($this->stateBySource[$version][$source_module])) {
+      // No declared state.
+      return MigrationState::NOT_FINISHED;
+    }
     if (in_array(MigrationState::NOT_FINISHED, $this->stateBySource[$version][$source_module], TRUE) || !in_array(MigrationState::FINISHED, $this->stateBySource[$version][$source_module], TRUE)) {
       return MigrationState::NOT_FINISHED;
     }
diff --git a/core/modules/migrate_drupal/tests/modules/migrate_state_no_file_test/migrate_state_no_file_test.info.yml b/core/modules/migrate_drupal/tests/modules/migrate_state_no_file_test/migrate_state_no_file_test.info.yml
deleted file mode 100644
index 975d292009f..00000000000
--- a/core/modules/migrate_drupal/tests/modules/migrate_state_no_file_test/migrate_state_no_file_test.info.yml
+++ /dev/null
@@ -1,5 +0,0 @@
-name: Migrate state no migrate_drupal.yml file test
-type: module
-description: Has a migration but Does not have a migrate_drupal.yml file.
-package: Testing
-version: VERSION
diff --git a/core/modules/migrate_drupal/tests/modules/migrate_state_no_file_test/migrations/migrate_state_no_file_test.yml b/core/modules/migrate_drupal/tests/modules/migrate_state_no_file_test/migrations/migrate_state_no_file_test.yml
deleted file mode 100644
index a6fd9622e33..00000000000
--- a/core/modules/migrate_drupal/tests/modules/migrate_state_no_file_test/migrations/migrate_state_no_file_test.yml
+++ /dev/null
@@ -1,19 +0,0 @@
-id: migrate_state_no_file_test
-label: Test
-migration_tags:
-  - Drupal 6
-  - Drupal 7
-  - Configuration
-source:
-  plugin: embedded_data
-  data_rows:
-    -
-      id: 1
-  ids:
-    id:
-      type: string
-  source_module: migrate_state_no_file_test
-process: []
-destination:
-  plugin: entity:field_config
-  destination_module: migrate_state_no_file_test
diff --git a/core/modules/migrate_drupal/tests/src/Kernel/MigrationStateDeprecationTest.php b/core/modules/migrate_drupal/tests/src/Kernel/MigrationStateDeprecationTest.php
deleted file mode 100644
index 41810f6fd96..00000000000
--- a/core/modules/migrate_drupal/tests/src/Kernel/MigrationStateDeprecationTest.php
+++ /dev/null
@@ -1,48 +0,0 @@
-<?php
-
-namespace Drupal\Tests\migrate_drupal\Kernel;
-
-use Drupal\KernelTests\KernelTestBase;
-
-/**
- * Defines a class for testing deprecation error from MigrationState.
- *
- * @group migrate_drupal
- * @group legacy
- */
-class MigrationStateDeprecationTest extends KernelTestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  protected static $modules = [
-    'migrate_drupal',
-    'migrate',
-    'migrate_state_no_file_test',
-  ];
-
-  /**
-   * Tests migration state deprecation notice.
-   *
-   * Test that a module with a migration but without a .migrate_drupal.yml
-   * trigger deprecation errors.
-   *
-   * @doesNotPerformAssertions
-   * @expectedDeprecation Using migration plugin definitions to determine the migration state of the module 'migrate_state_no_file_test' is deprecated in Drupal 8.7. Add the module to a migrate_drupal.yml file. See https://www.drupal.org/node/2929443
-   */
-  public function testUndeclaredDestinationDeprecation() {
-    $plugin_manager = \Drupal::service('plugin.manager.migration');
-    $all_migrations = $plugin_manager->createInstancesByTag('Drupal 7');
-
-    \Drupal::service('migrate_drupal.migration_state')
-      ->getUpgradeStates(7, [
-        'module' => [
-          'migrate_state_no_file_test' => [
-            'name' => 'migrate_state_no_file_test',
-            'status' => TRUE,
-          ],
-        ],
-      ], ['import' => $all_migrations['migrate_state_no_file_test']]);
-  }
-
-}
diff --git a/core/modules/migrate_drupal/tests/src/Kernel/StateFileExists.php b/core/modules/migrate_drupal/tests/src/Kernel/StateFileExists.php
index 240fd8fb466..1940009eb3d 100644
--- a/core/modules/migrate_drupal/tests/src/Kernel/StateFileExists.php
+++ b/core/modules/migrate_drupal/tests/src/Kernel/StateFileExists.php
@@ -28,8 +28,6 @@ class StateFileExists extends MigrateDrupalTestBase {
     // Test migrations states.
     'migrate_state_finished_test',
     'migrate_state_not_finished_test',
-    // Test missing migrate_drupal.yml.
-    'migrate_state_no_file_test',
   ];
 
   /**
diff --git a/core/modules/migrate_drupal/tests/src/Unit/MigrationStateUnitTest.php b/core/modules/migrate_drupal/tests/src/Unit/MigrationStateUnitTest.php
index b4fd9113068..57c72e1cfc3 100644
--- a/core/modules/migrate_drupal/tests/src/Unit/MigrationStateUnitTest.php
+++ b/core/modules/migrate_drupal/tests/src/Unit/MigrationStateUnitTest.php
@@ -258,11 +258,12 @@ PROFILE
           'search' => '',
           // Declared finished by one module but not finished by another.
           'user' => 'user',
+          // Enabled and not declared.
+          'rdf' => 'rdf',
+          'link' => 'link',
         ],
         MigrationState::FINISHED => [
-          'link' => 'link',
           'node' => 'node',
-          'rdf' => 'rdf',
         ],
       ],
       'expected_6' => [
@@ -279,12 +280,11 @@ PROFILE
           // No discovered or declared state.
           'search' => '',
           'color' => '',
+          'link' => 'link',
         ],
         MigrationState::FINISHED => [
           'node' => 'node',
           'content' => 'node',
-          // Update path not needed.
-          'link' => 'link',
         ],
       ],
     ];
diff --git a/core/modules/migrate_drupal_ui/tests/src/Functional/d6/MultilingualReviewPageTest.php b/core/modules/migrate_drupal_ui/tests/src/Functional/d6/MultilingualReviewPageTest.php
index dc3a6d68eb9..37bc184a8f6 100644
--- a/core/modules/migrate_drupal_ui/tests/src/Functional/d6/MultilingualReviewPageTest.php
+++ b/core/modules/migrate_drupal_ui/tests/src/Functional/d6/MultilingualReviewPageTest.php
@@ -37,8 +37,6 @@ class MultilingualReviewPageTest extends MultilingualReviewPageTestBase {
     'migrate_state_finished_test',
     'migrate_state_not_finished_test',
     // Test missing migrate_drupal.yml.
-    'migrate_state_no_file_test',
-    // Test missing migrate_drupal.yml.
     'migrate_state_no_upgrade_path',
   ];
 
diff --git a/core/modules/migrate_drupal_ui/tests/src/Functional/d6/NoMultilingualReviewPageTest.php b/core/modules/migrate_drupal_ui/tests/src/Functional/d6/NoMultilingualReviewPageTest.php
index 469a73ca892..4ad7fb7a4cc 100644
--- a/core/modules/migrate_drupal_ui/tests/src/Functional/d6/NoMultilingualReviewPageTest.php
+++ b/core/modules/migrate_drupal_ui/tests/src/Functional/d6/NoMultilingualReviewPageTest.php
@@ -33,8 +33,6 @@ class NoMultilingualReviewPageTest extends NoMultilingualReviewPageTestBase {
     // Test migrations states.
     'migrate_state_finished_test',
     'migrate_state_not_finished_test',
-    // Test missing migrate_drupal.yml.
-    'migrate_state_no_file_test',
   ];
 
   /**
diff --git a/core/modules/migrate_drupal_ui/tests/src/Functional/d7/MultilingualReviewPageTest.php b/core/modules/migrate_drupal_ui/tests/src/Functional/d7/MultilingualReviewPageTest.php
index b5fdc0239bc..5a8be987067 100644
--- a/core/modules/migrate_drupal_ui/tests/src/Functional/d7/MultilingualReviewPageTest.php
+++ b/core/modules/migrate_drupal_ui/tests/src/Functional/d7/MultilingualReviewPageTest.php
@@ -35,8 +35,6 @@ class MultilingualReviewPageTest extends MultilingualReviewPageTestBase {
     // Test migrations states.
     'migrate_state_finished_test',
     'migrate_state_not_finished_test',
-    // Test missing migrate_drupal.yml.
-    'migrate_state_no_file_test',
   ];
 
   /**