updated core to 8.6.1 via composer

core/modules/language/migrations/d6_language_content_menu_settings.yml

@@ -0,0 +1,21 @@
+id: d6_language_content_menu_settings
+label: Drupal 6 language content menu settings
+migration_tags:
+  - Drupal 6
+  - Configuration
+source:
+  plugin: extension
+  name: i18nmenu
+  constants:
+    target_type: 'menu_link_content'
+    langcode: 'site_default'
+process:
+  target_entity_type_id: 'constants/target_type'
+  # menu_link_content has a bundle key but no bundle support so use the entity
+  # type as the bundle.
+  target_bundle: 'constants/target_type'
+  default_langcode: 'constants/langcode'
+  # Drupal 6 menus are translated when the i18nmenu module is enabled.
+  language_alterable: status
+destination:
+  plugin: entity:language_content_settings

core/modules/language/migrations/d7_language_content_settings.yml

@@ -20,6 +20,8 @@ process:
         0: NULL
         1: 'current_interface'
         2: 'current_interface'
+        4: 'und'
+      default_value: NULL
     -
       plugin: skip_on_empty
       method: row
@@ -38,6 +40,7 @@ process:
       0: NULL
       1: false
       2: true
+      4: true
 destination:
   plugin: entity:language_content_settings
   content_translation_update_definitions: