/resources/customer_negative_criterion.proto 

--- v16/resources/customer_negative_criterion.proto 2024-04-18 17:10:06.000000000 +0000
+++ v16-1/resources/customer_negative_criterion.proto   2024-04-18 17:10:15.000000000 +0000
@@ -88,5 +88,9 @@
     // Immutable. NegativeKeywordList.
     google.ads.googleads.v16.common.NegativeKeywordListInfo
         negative_keyword_list = 11 [(google.api.field_behavior) = IMMUTABLE];
+
+    // Immutable. IPBLock
+    google.ads.googleads.v16.common.IpBlockInfo ip_block = 12
+        [(google.api.field_behavior) = IMMUTABLE];
   }
 }