diff --git a/CHANGELOG.md b/CHANGELOG.md
index b4ce7e4e..ca6b0d21 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,6 @@
 ## placeholder
+* Update protobuf definitions to include new properties in OrchestratorRequest and update source commit hash ([#214](https://github.com/microsoft/durabletask-java/pull/214))
+## v1.5.1.preview
 * DTS Support ([#201](https://github.com/microsoft/durabletask-java/pull/201))
 * Add automatic proto file download and commit hash tracking during build ([#207](https://github.com/microsoft/durabletask-java/pull/207))
 * Fix infinite loop when use continueasnew after wait external event ([#183](https://github.com/microsoft/durabletask-java/pull/183))
diff --git a/internal/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH b/internal/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH
index 5fe0edd4..3d3f9e98 100644
--- a/internal/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH
+++ b/internal/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH
@@ -1 +1 @@
-c85ef11430ff8e10e21105abb545b0803bb86c66
\ No newline at end of file
+fbe5bb20835678099fc51a44993ed9b045dee5a6
\ No newline at end of file
diff --git a/internal/durabletask-protobuf/protos/orchestrator_service.proto b/internal/durabletask-protobuf/protos/orchestrator_service.proto
index 5dd39cfe..88928c3b 100644
--- a/internal/durabletask-protobuf/protos/orchestrator_service.proto
+++ b/internal/durabletask-protobuf/protos/orchestrator_service.proto
@@ -11,6 +11,7 @@ import "google/protobuf/timestamp.proto";
 import "google/protobuf/duration.proto";
 import "google/protobuf/wrappers.proto";
 import "google/protobuf/empty.proto";
+import "google/protobuf/struct.proto";
 
 message OrchestrationInstance {
     string instanceId = 1;
@@ -318,6 +319,7 @@ message OrchestratorRequest {
     repeated HistoryEvent newEvents = 4;
     OrchestratorEntityParameters entityParameters = 5;
     bool requiresHistoryStreaming = 6;
+    map<string, google.protobuf.Value> properties = 7;
 }
 
 message OrchestratorResponse {