/resources/customer.proto

--- v18/resources/customer.proto    2025-08-05 14:36:07.000000000 +0000
+++ v19/resources/customer.proto    2025-08-05 14:36:20.000000000 +0000
@@ -95,9 +96,9 @@
   // operation.
   CallReportingSetting call_reporting_setting = 10;

-  // Output only. Conversion tracking setting for a customer.
+  // Immutable. Conversion tracking setting for a customer.
   ConversionTrackingSetting conversion_tracking_setting = 14
-      [(google.api.field_behavior) = OUTPUT_ONLY];
+      [(google.api.field_behavior) = IMMUTABLE];

   // Output only. Remarketing setting for a customer.
   RemarketingSetting remarketing_setting = 15
@@ -235,10 +236,10 @@
   bool enhanced_conversions_for_leads_enabled = 7
       [(google.api.field_behavior) = OUTPUT_ONLY];

-  // Output only. The resource name of the customer where conversions are
-  // created and managed. This field is read-only.
+  // Immutable. The resource name of the customer where conversions are created
+  // and managed. This field is read-only.
   string google_ads_conversion_customer = 8
-      [(google.api.field_behavior) = OUTPUT_ONLY];
+      [(google.api.field_behavior) = IMMUTABLE];
 }

 // Remarketing setting for a customer.