diff --git a/_config/middleware.yml b/_config/middleware.yml
index beb0a93..5cbf9ca 100644
--- a/_config/middleware.yml
+++ b/_config/middleware.yml
@@ -8,3 +8,5 @@ SilverStripe\Core\Injector\Injector:
     properties:
       Middlewares:
         SubsitesStateMiddleware: %$SilverStripe\Subsites\Middleware\InitStateMiddleware
+  SilverStripe\Dev\Tasks\MigrateFileTask:
+    class: SilverStripe\Subsites\Tasks\SubsiteMigrateFileTask
diff --git a/src/Middleware/InitStateMiddleware.php b/src/Middleware/InitStateMiddleware.php
index 4b7cd30..f87369a 100644
--- a/src/Middleware/InitStateMiddleware.php
+++ b/src/Middleware/InitStateMiddleware.php
@@ -66,7 +66,7 @@ class InitStateMiddleware implements HTTPMiddleware
     public function getIsAdmin(HTTPRequest $request)
     {
         $adminPaths = static::config()->get('admin_url_paths');
-        $adminPaths[] = AdminRootController::config()->get('url_base') . '/';
+        $adminPaths[] = AdminRootController::admin_url();
         $currentPath = rtrim($request->getURL(), '/') . '/';
         foreach ($adminPaths as $adminPath) {
             if (substr($currentPath, 0, strlen($adminPath)) === $adminPath) {
diff --git a/src/Tasks/SubsiteMigrateFileTask.php b/src/Tasks/SubsiteMigrateFileTask.php
new file mode 100644
index 0000000..c00c776
--- /dev/null
+++ b/src/Tasks/SubsiteMigrateFileTask.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace SilverStripe\Subsites\Tasks;
+
+use SilverStripe\Dev\Tasks\MigrateFileTask;
+use SilverStripe\Subsites\Model\Subsite;
+
+class SubsiteMigrateFileTask extends MigrateFileTask
+{
+    public function run($request)
+    {
+        $origDisableSubsiteFilter = Subsite::$disable_subsite_filter;
+        Subsite::disable_subsite_filter(true);
+
+        parent::run($request);
+
+        Subsite::disable_subsite_filter($origDisableSubsiteFilter);
+    }
+}