diff --git a/agent/test/Makefile b/agent/test/Makefile
index 54bb780..a6e983d 100644
--- a/agent/test/Makefile
+++ b/agent/test/Makefile
@@ -21,7 +21,7 @@
 TOP_DIR=`pwd`
 OPENOLTDEVICE ?= asfvolt16
 
-OPENOLT_PROTO_VER ?= v4.1.5
+OPENOLT_PROTO_VER ?= v4.2.0
 
 ########################################################################
 ##