diff --git a/app/Services/Paddle/PaddleClient.php b/app/Services/Paddle/PaddleClient.php
index 637c33a..e217d1a 100644
--- a/app/Services/Paddle/PaddleClient.php
+++ b/app/Services/Paddle/PaddleClient.php
@@ -70,6 +70,7 @@ class PaddleClient
         $headers = [
             'User-Agent' => sprintf('FotospielApp/%s PaddleClient', app()->version()),
             'Paddle-Environment' => Str::lower($environment) === 'sandbox' ? 'sandbox' : 'production',
+            'Paddle-Version' => '1',
         ];
 
         return $this->http
diff --git a/tests/Feature/Api/Tenant/BillingPortalTest.php b/tests/Feature/Api/Tenant/BillingPortalTest.php
index c3b2c23..dc36146 100644
--- a/tests/Feature/Api/Tenant/BillingPortalTest.php
+++ b/tests/Feature/Api/Tenant/BillingPortalTest.php
@@ -32,6 +32,8 @@ class BillingPortalTest extends TenantTestCase
         $response->assertOk();
         $response->assertJsonPath('url', 'https://portal.example/overview');
 
+        Http::assertSent(fn (Request $request) => $request->hasHeader('Paddle-Version', '1'));
+
         $this->assertDatabaseHas('tenants', [
             'id' => $this->tenant->id,
             'paddle_customer_id' => 'cus_123',