diff --git a/native/cpp/CommonCpp/grpc/protos/tunnelbroker.proto b/native/cpp/CommonCpp/grpc/protos/tunnelbroker.proto
index d871b019a..49b51908a 100644
--- a/native/cpp/CommonCpp/grpc/protos/tunnelbroker.proto
+++ b/native/cpp/CommonCpp/grpc/protos/tunnelbroker.proto
@@ -1,106 +1,122 @@
 syntax = "proto3";
 
 package tunnelbroker;
 
 import "google/protobuf/empty.proto";
 
 service TunnelbrokerService {
 
   // The old API service methods
   // to support the native client build
   // until we switch to the new one
   
   rpc CheckIfPrimaryDeviceOnline(CheckRequest) returns (CheckResponse) {}
   rpc BecomeNewPrimaryDevice(NewPrimaryRequest) returns (NewPrimaryResponse) {}
   rpc SendPong (PongRequest) returns (google.protobuf.Empty) {}
 
   // New API service methods
 
   rpc SessionSignature(SessionSignatureRequest) returns (SessionSignatureResponse) {}
   rpc NewSession(NewSessionRequest) returns (NewSessionResponse) {}
   rpc Send(SendRequest) returns (google.protobuf.Empty) {}
   rpc Get(GetRequest) returns (stream GetResponse) {}
+
+  // Replacing Send and Get with a single bidirectional streaming RPC
+  rpc OpenStream(stream OutboundMessage) returns (stream InboundMessage) {}
 }
 
 // Session
 
 message SessionSignatureRequest {
   string deviceID = 1;
 }
 
 message SessionSignatureResponse {
   string toSign = 1;
 }
 
 message NewSessionRequest {
   string deviceID = 1;
   bytes publicKey = 2;
   string signature = 3;
   optional string notifyToken = 4;
   DeviceTypes deviceType = 5;
   string deviceAppVersion = 6;
   string deviceOS = 7;
   // Nested enum devices type
   enum DeviceTypes {
     MOBILE = 0;
     WEB = 1;
     KEYSERVER = 2;
   }
 }
 
 message NewSessionResponse {
   string sessionID = 1;
 }
 
 // Send payload to device
 
 message SendRequest {
   string sessionID = 1;
   string toDeviceID = 2;
   bytes payload = 3;
   repeated string blobHashes = 4;
 }
 
 // Get messages from devices
 
 message GetRequest {
   string sessionID = 1;
 }
 
 message GetResponse {
   string fromDeviceID = 1;
   bytes payload = 2;
   repeated string blobHashes = 3;
 }
 
+message OutboundMessage {
+  string toDeviceID = 1;
+  string payload = 2;
+  repeated string blobHashes = 3;
+}
+
+message InboundMessage {
+  string fromDeviceID = 1;
+  string fromConnectionID = 2;
+  string payload = 3;
+  repeated string blobHashes = 4;
+}
+
 // Old API structures
 
 enum CheckResponseType {
   PRIMARY_DOESNT_EXIST = 0;
   PRIMARY_ONLINE = 1;
   PRIMARY_OFFLINE = 2;
   CURRENT_IS_PRIMARY = 3;
 }
 
 message CheckRequest {
   string userId = 1;
   string deviceToken = 2;
 }
 
 message CheckResponse {
   CheckResponseType checkResponseType = 1;
 }
 
 message NewPrimaryRequest {
   string userId = 1;
   string deviceToken = 2;
 }
 
 message NewPrimaryResponse {
   bool success = 1;
 }
 
 message PongRequest {
   string userId = 1;
   string deviceToken = 2;
 }