diff --git a/config/optional/migrate.migration.d7_simplenews_newsletter.yml b/migration_templates/d7_simplenews_newsletter.yml
similarity index 100%
rename from config/optional/migrate.migration.d7_simplenews_newsletter.yml
rename to migration_templates/d7_simplenews_newsletter.yml
diff --git a/config/optional/migrate.migration.d7_simplenews_subscriber.yml b/migration_templates/d7_simplenews_subscriber.yml
similarity index 100%
rename from config/optional/migrate.migration.d7_simplenews_subscriber.yml
rename to migration_templates/d7_simplenews_subscriber.yml
diff --git a/src/Plugin/migrate/source/d7/Newsletter.php b/src/Plugin/migrate/source/d7/Newsletter.php
index 2599f0b..91acb69 100644
--- a/src/Plugin/migrate/source/d7/Newsletter.php
+++ b/src/Plugin/migrate/source/d7/Newsletter.php
@@ -42,7 +42,7 @@ class Newsletter extends DrupalSqlBase {
    * {@inheritdoc}
    */
   public function getIds() {
-    return ['newsletter_id' => ['type' => 'string']];
+    return ['newsletter_id' => ['type' => 'serial']];
   }
 
   /**
diff --git a/src/Plugin/migrate/source/d7/Subscriber.php b/src/Plugin/migrate/source/d7/Subscriber.php
index 7e3826d..9421b66 100644
--- a/src/Plugin/migrate/source/d7/Subscriber.php
+++ b/src/Plugin/migrate/source/d7/Subscriber.php
@@ -36,7 +36,7 @@ class Subscriber extends DrupalSqlBase {
    * {@inheritdoc}
    */
   public function getIds() {
-    return ['snid' => ['type' => 'integer']];
+    return ['snid' => ['type' => 'serial']];
   }
 
   /**