diff --git a/fuchsia/include/fuchsia_communication.h b/fuchsia/include/fuchsia_communication.h
index d261efe..6b9054b 100644
--- a/fuchsia/include/fuchsia_communication.h
+++ b/fuchsia/include/fuchsia_communication.h
@@ -13,14 +13,22 @@
 	kSemaphoreMax,
 };
 
+enum PayloadVersion
+{
+	kPayloadVersion0 = 0,
+};
+
 struct FuchsiaImgCommandPayload
 {
+	// This should be the version number of this payload struct.
+	uint32_t payload_version;
+
 	// The bridge sets this to nonzero when it finishes executing the bridge
 	// command and modifying the output data.
-	uint32_t finished_command;
+	uint16_t finished_command;
 
 	// The bridge sets this to nonzero if the last command succeeded.
-	uint32_t success;
+	uint16_t success;
 
 	uint64_t thread_id;