diff --git a/media/bufferpool/2.0/IAccessor.hal b/media/bufferpool/2.0/IAccessor.hal
index 66707fe..b889518 100644
--- a/media/bufferpool/2.0/IAccessor.hal
+++ b/media/bufferpool/2.0/IAccessor.hal
@@ -67,6 +67,7 @@
      *     to get shared buffers from the buffer pool.
      * @return connectionId Id of IConnection. The Id identifies
      *     sender and receiver in FMQ messages during buffer transfer.
+     * @return msgId Id of the most recent message from buffer pool.
      * @return toFmqDesc FMQ descriptor. The descriptor is used to
      *     post buffer status messages.
      * @return fromFmqDesc FMQ descriptor. The descriptor is used to
@@ -75,6 +76,7 @@
     connect(IObserver observer)
         generates (ResultStatus status, IConnection connection,
                    int64_t connectionId,
+                   uint32_t msgId,
                    fmq_sync<BufferStatusMessage> toFmqDesc,
                    fmq_unsync<BufferInvalidationMessage> fromFmqDesc);
 };
diff --git a/media/bufferpool/2.0/IObserver.hal b/media/bufferpool/2.0/IObserver.hal
index a998836..62f247e 100644
--- a/media/bufferpool/2.0/IObserver.hal
+++ b/media/bufferpool/2.0/IObserver.hal
@@ -29,6 +29,7 @@
      * message.
      *
      * @param connectionId the connection Id of the specific buffer pool client
+     * @param msgId Id of the most recent message
      */
-    oneway onMessage(int64_t connectionId);
+    oneway onMessage(int64_t connectionId, uint32_t msgId);
 };