diff --git a/agent/test/Makefile.in b/agent/test/Makefile.in
index ffe5e3b..2122266 100644
--- a/agent/test/Makefile.in
+++ b/agent/test/Makefile.in
@@ -22,6 +22,11 @@
 TOP_DIR=`pwd`
 OPENOLTDEVICE ?= asfvolt16
 
+# OpenOLT Proto version.
+# This specifies the GIT tag in https://github.com/opencord/voltha-protos
+# repo that we need to refer to, to pick the right version of
+# openolt.proto and tech_profile.proto
+OPENOLT_PROTO_VER ?= v1.0.3
 
 # GRPC installation
 GRPC_ADDR = https://github.com/grpc/grpc
@@ -47,7 +52,7 @@
 LDFLAGS += `pkg-config --libs protobuf grpc++ grpc` -ldl -lgpr
 CXXFLAGSDEVICE = -I../device -I../device/$(OPENOLTDEVICE) -I../device/generic
 
-export CXX CXXFLAGS
+export CXX CXXFLAGS OPENOLT_PROTO_VER
 
 BAL_API_DIR=bal-api-3.1.0
 BALLIBNAME=bcm_host_api_stubs