Correct version of 1.31.1

Change-Id: Ib86e13280a289ecac4692415e1003d5b76f21601
diff --git a/Makefile b/Makefile
index dd5b86e..8ed64bf 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,7 @@
 PROTOC_SHA256SUM                ?= "a1b8ed22d6dc53c5b8680a6f1760a305b33ef471bece482e92728f00ba2a2969"
 PROTOC_GEN_GO_VERSION           ?= "1.3.2"
 PROTOC_GEN_GRPC_GATEWAY_VERSION ?= "1.14.3"
-PROTOC_GEN_CPP_VERSION          ?= "1.3.1"
+PROTOC_GEN_CPP_VERSION          ?= "1.31.1"
 
 # Docker related
 DOCKER_LABEL_VCS_DIRTY     = false
diff --git a/VERSION b/VERSION
index 73462a5..f225a78 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.5.1
+2.5.2