diff --git a/lib/sock/Makefile b/lib/sock/Makefile
index 9556485ec..9468676cc 100644
--- a/lib/sock/Makefile
+++ b/lib/sock/Makefile
@@ -34,7 +34,7 @@
 SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
-SO_VER := 5
+SO_VER := 4
 SO_MINOR := 0
 
 C_SRCS = sock.c sock_rpc.c