Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

core/modules/contact/migration_templates/contact_category.yml

@@ -1,9 +1,10 @@
-id: d6_contact_category
-label: Drupal 6 contact category configuration
+id: contact_category
+label: Contact category configuration
 migration_tags:
   - Drupal 6
+  - Drupal 7
 source:
-  plugin: d6_contact_category
+  plugin: contact_category
 process:
   id:
     -

core/modules/contact/migration_templates/d6_contact_settings.yml

@@ -1,9 +1,9 @@
 id: d6_contact_settings
-label: Drupal 6 contact configuration
+label: Contact configuration
 migration_tags:
   - Drupal 6
 source:
-  plugin: d6_contact_settings
+  plugin: contact_settings
   variables:
     - contact_default_status
     - contact_hourly_threshold
@@ -12,11 +12,11 @@ process:
   'flood/limit': contact_hourly_threshold
   default_form:
     plugin: migration
-    migration: d6_contact_category
+    migration: contact_category
     source: default_category
 destination:
   plugin: config
   config_name: contact.settings
 migration_dependencies:
   required:
-    - d6_contact_category
+    - contact_category

core/modules/contact/migration_templates/d7_contact_settings.yml

@@ -0,0 +1,28 @@
+id: d7_contact_settings
+label: Contact configuration
+migration_tags:
+  - Drupal 7
+source:
+  plugin: contact_settings
+  variables:
+    - contact_default_status
+    - contact_threshold_limit
+process:
+  user_default_enabled: contact_default_status
+  'flood/limit': contact_threshold_limit
+  default_form:
+    plugin: migration
+    migration: contact_category
+    source: default_category
+destination:
+  plugin: config
+  config_name: contact.settings
+migration_dependencies:
+  required:
+    - contact_category
+dependencies:
+  config:
+    - migrate.migration.contact_category
+  module:
+    - contact
+    - migrate_drupal