diff --git a/_config.php b/_config.php
deleted file mode 100644
index 93cca78..0000000
--- a/_config.php
+++ /dev/null
@@ -1,44 +0,0 @@
-<?php
-
-use SilverStripe\CMS\Model\SiteTree;
-use SilverStripe\CMS\Controllers\ContentController;
-use SilverStripe\CMS\Controllers\CMSPageAddController;
-use SilverStripe\Admin\LeftAndMain;
-use SilverStripe\Security\Group;
-use SilverStripe\Assets\File;
-use SilverStripe\CMS\Model\ErrorPage;
-use SilverStripe\SiteConfig\SiteConfig;
-use SilverStripe\SiteConfig\SiteConfigLeftAndMain;
-use SilverStripe\Reports\Report;
-use SilverStripe\Admin\SecurityAdmin;
-use SilverStripe\CMS\Controllers\CMSMain;
-use SilverStripe\CMS\Controllers\CMSPagesController;
-use SilverStripe\CMS\Controllers\CMSPageSettingsController;
-use SilverStripe\AssetAdmin\Controller\AssetAdmin;
-
-/**
- * The subsites module modifies the behaviour of the CMS - in the SiteTree and Group databases - to store information
- * about a number of sub-sites, rather than a single site.
- */
-
-SiteTree::add_extension('SiteTreeSubsites');
-ContentController::add_extension('ControllerSubsites');
-CMSPageAddController::add_extension('CMSPageAddControllerExtension');
-LeftAndMain::add_extension('LeftAndMainSubsites');
-LeftAndMain::add_extension('ControllerSubsites');
-
-Group::add_extension('GroupSubsites');
-File::add_extension('FileSubsites');
-ErrorPage::add_extension('ErrorPageSubsite');
-SiteConfig::add_extension('SiteConfigSubsites');
-
-Report::add_excluded_reports('SubsiteReportWrapper');
-
-//Display in cms menu
-AssetAdmin::add_extension('SubsiteMenuExtension');
-SecurityAdmin::add_extension('SubsiteMenuExtension');
-CMSMain::add_extension('SubsiteMenuExtension');
-CMSPagesController::add_extension('SubsiteMenuExtension');
-SubsiteAdmin::add_extension('SubsiteMenuExtension');
-SiteConfigLeftAndMain::add_extension('SubsiteMenuExtension');
-
diff --git a/_config/config.yml b/_config/config.yml
index 5f12d39..6cd3018 100644
--- a/_config/config.yml
+++ b/_config/config.yml
@@ -1,9 +1,50 @@
 ---
 Name: subsiteconfig
 ---
-SilverStripe\AssetAdmin\Controller\AssetAdmin:
-  treats_subsite_0_as_global: true
-
 SilverStripe\Control\Director:
   rules:
-    'SubsiteXHRController': 'SubsiteXHRController'
+    SubsiteXHRController: SilverStripe\Subsites\Controller\SubsiteXHRController
+SilverStripe\AssetAdmin\Controller\AssetAdmin:
+  treats_subsite_0_as_global: true
+  extensions:
+    - SilverStripe\Subsites\Extensions\SubsiteMenuExtension
+SilverStripe\CMS\Model\SiteTree:
+  extensions:
+    - SilverStripe\Subsites\Extensions\SiteTreeSubsites
+SilverStripe\CMS\Controllers\ContentController:
+  extensions:
+    - SilverStripe\Subsites\Extensions\ControllerSubsites
+SilverStripe\CMS\Controllers\CMSPageAddController:
+  extensions:
+    - SilverStripe\Subsites\Extensions\CMSPageAddControllerExtension
+SilverStripe\Admin\LeftAndMain:
+  extensions:
+    - SilverStripe\Subsites\Extensions\LeftAndMainSubsites
+    - SilverStripe\Subsites\Extensions\ControllerSubsites
+SilverStripe\Security\Group:
+  extensions:
+    - SilverStripe\Subsites\Extensions\GroupSubsites
+SilverStripe\Assets\File:
+  extensions:
+    - SilverStripe\Subsites\Extensions\FileSubsites
+SilverStripe\CMS\Model\ErrorPage:
+  extensions:
+    - SilverStripe\Subsites\Extensions\ErrorPageSubsite
+SilverStripe\SiteConfig\SiteConfig:
+  extensions:
+    - SilverStripe\Subsites\Extensions\SiteConfigSubsites
+Report:
+  extensions:
+    - SilverStripe\Subsites\Reports\SubsiteReportWrapper
+SilverStripe\Admin\SecurityAdmin:
+  extensions:
+    - SilverStripe\Subsites\Extensions\SubsiteMenuExtension
+SilverStripe\CMS\Controllers\CMSMain:
+  extensions:
+    - SilverStripe\Subsites\Extensions\SubsiteMenuExtension
+SilverStripe\CMS\Controllers\CMSPagesController:
+  extensions:
+    - SilverStripe\Subsites\Extensions\SubsiteMenuExtension
+SilverStripe\Subsites\Admin\SubsiteAdmin:
+  extensions:
+    - SilverStripe\Subsites\Extensions\SubsiteMenuExtension