diff --git a/backend/src/controllers/customer.controller.ts b/backend/src/controllers/customer.controller.ts
index 6759e20b..4b435c6b 100644
--- a/backend/src/controllers/customer.controller.ts
+++ b/backend/src/controllers/customer.controller.ts
@@ -88,6 +88,9 @@ export async function updateCustomer(req: Request, res: Response): Promise<void>
         salutation: 'Anrede', firstName: 'Vorname', lastName: 'Nachname', email: 'E-Mail',
         phone: 'Telefon', mobile: 'Mobil', birthDate: 'Geburtsdatum', birthPlace: 'Geburtsort',
         companyName: 'Firma', type: 'Typ', taxNumber: 'Steuernummer', notes: 'Notizen',
+        useInformalAddress: 'Anrede per',
+        autoBirthdayGreeting: 'Autom. Geburtstagsgruß',
+        autoBirthdayChannel: 'Kanal für Geburtstagsgruß',
       };
       for (const [key, value] of Object.entries(data)) {
         // Technische/interne Felder überspringen
diff --git a/backend/src/services/customer.service.ts b/backend/src/services/customer.service.ts
index 32e9287a..755abf7b 100644
--- a/backend/src/services/customer.service.ts
+++ b/backend/src/services/customer.service.ts
@@ -136,6 +136,7 @@ export async function updateCustomer(
   data: {
     type?: CustomerType;
     salutation?: string;
+    useInformalAddress?: boolean;
     firstName?: string;
     lastName?: string;
     companyName?: string;
@@ -148,6 +149,8 @@ export async function updateCustomer(
     businessRegistration?: string;
     commercialRegister?: string;
     notes?: string;
+    autoBirthdayGreeting?: boolean;
+    autoBirthdayChannel?: string | null;
   }
 ) {
   return prisma.customer.update({
diff --git a/frontend/src/pages/customers/CustomerForm.tsx b/frontend/src/pages/customers/CustomerForm.tsx
index f0d15cf7..6f8b7254 100644
--- a/frontend/src/pages/customers/CustomerForm.tsx
+++ b/frontend/src/pages/customers/CustomerForm.tsx
@@ -39,6 +39,8 @@ export default function CustomerForm() {
       if (data.foundingDate) {
         data.foundingDate = data.foundingDate.split('T')[0] as any;
       }
+      // Boolean → String für <select>-Wert ('true'/'false')
+      (data as any).useInformalAddress = data.useInformalAddress === true ? 'true' : 'false';
       reset(data);
     }
   }, [customer, reset]);
@@ -65,6 +67,9 @@ export default function CustomerForm() {
     const submitData: any = {
       type: data.type,
       salutation: data.salutation || '',
+      useInformalAddress:
+        data.useInformalAddress === true ||
+        (data.useInformalAddress as any) === 'true',
       firstName: data.firstName,
       lastName: data.lastName,
       companyName: data.companyName || '',