diff --git a/src/objective-c/GRPCClient/GRPCCall+ChannelArg.m b/src/objective-c/GRPCClient/GRPCCall+ChannelArg.m
index 0248f33638b..805e54b8900 100644
--- a/src/objective-c/GRPCClient/GRPCCall+ChannelArg.m
+++ b/src/objective-c/GRPCClient/GRPCCall+ChannelArg.m
@@ -53,6 +53,7 @@
       break;
     default:
       NSLog(@"Invalid compression algorithm");
+      abort();
   }
 }
 
diff --git a/src/objective-c/tests/RemoteTestClient/messages.proto b/src/objective-c/tests/RemoteTestClient/messages.proto
index ac46ec5d8d8..342e91d5aab 100644
--- a/src/objective-c/tests/RemoteTestClient/messages.proto
+++ b/src/objective-c/tests/RemoteTestClient/messages.proto
@@ -20,44 +20,45 @@ package grpc.testing;
 
 option objc_class_prefix = "RMT";
 
+// TODO(dgq): Go back to using well-known types once
+// https://github.com/grpc/grpc/issues/6980 has been fixed.
+// import "google/protobuf/wrappers.proto";
 message BoolValue {
   // The bool value.
   bool value = 1;
 }
 
-message EchoStatus {
-  int32 code = 1;
-  string message = 2;
-}
-
+// DEPRECATED, don't use. To be removed shortly.
 // The type of payload that should be returned.
 enum PayloadType {
   // Compressable text format.
   COMPRESSABLE = 0;
-
-  // Uncompressable binary format.
-  UNCOMPRESSABLE = 1;
-
-  // Randomly chosen from all other formats defined in this enum.
-  RANDOM = 2;
 }
 
 // A block of data, to simply increase gRPC message size.
 message Payload {
+  // DEPRECATED, don't use. To be removed shortly.
   // The type of data in body.
   PayloadType type = 1;
   // Primary contents of payload.
   bytes body = 2;
 }
 
+// A protobuf representation for grpc status. This is used by test
+// clients to specify a status that the server should attempt to return.
+message EchoStatus {
+  int32 code = 1;
+  string message = 2;
+}
+
 // Unary request.
 message SimpleRequest {
+  // DEPRECATED, don't use. To be removed shortly.
   // Desired payload type in the response from the server.
   // If response_type is RANDOM, server randomly chooses one from other formats.
   PayloadType response_type = 1;
 
   // Desired payload size in the response from the server.
-  // If response_type is COMPRESSABLE, this denotes the size before compression.
   int32 response_size = 2;
 
   // Optional input payload sent along with the request.
@@ -98,6 +99,12 @@ message StreamingInputCallRequest {
   // Optional input payload sent along with the request.
   Payload payload = 1;
 
+  // Whether the server should expect this request to be compressed. This field
+  // is "nullable" in order to interoperate seamlessly with servers not able to
+  // implement the full compression tests by introspecting the call to verify
+  // the request's compression status.
+  BoolValue expect_compressed = 2;
+
   // Not expecting any payload from the response.
 }
 
@@ -110,16 +117,22 @@ message StreamingInputCallResponse {
 // Configuration for a particular response.
 message ResponseParameters {
   // Desired payload sizes in responses from the server.
-  // If response_type is COMPRESSABLE, this denotes the size before compression.
   int32 size = 1;
 
   // Desired interval between consecutive responses in the response stream in
   // microseconds.
   int32 interval_us = 2;
+
+  // Whether to request the server to compress the response. This field is
+  // "nullable" in order to interoperate seamlessly with clients not able to
+  // implement the full compression tests by introspecting the call to verify
+  // the response's compression status.
+  BoolValue compressed = 3;
 }
 
 // Server-streaming request.
 message StreamingOutputCallRequest {
+  // DEPRECATED, don't use. To be removed shortly.
   // Desired payload type in the response from the server.
   // If response_type is RANDOM, the payload from each response in the stream
   // might be of different types. This is to simulate a mixed type of payload
@@ -131,6 +144,9 @@ message StreamingOutputCallRequest {
 
   // Optional input payload sent along with the request.
   Payload payload = 3;
+
+  // Whether server should return a given status
+  EchoStatus response_status = 7;
 }
 
 // Server-streaming response, as configured by the request and parameters.
@@ -138,3 +154,17 @@ message StreamingOutputCallResponse {
   // Payload to increase response size.
   Payload payload = 1;
 }
+
+// For reconnect interop test only.
+// Client tells server what reconnection parameters it used.
+message ReconnectParams {
+  int32 max_reconnect_backoff_ms = 1;
+}
+
+// For reconnect interop test only.
+// Server tells client whether its reconnects are following the spec and the
+// reconnect backoffs it saw.
+message ReconnectInfo {
+  bool passed = 1;
+  repeated int32 backoff_ms = 2;
+}