diff --git a/configure.in b/configure.in
index 32d906e3..3d2247e1 100644
--- a/configure.in
+++ b/configure.in
@@ -1,6 +1,6 @@
 AC_INIT(msgpack/unpack_template.h)
 AC_CONFIG_AUX_DIR(ac)
-AM_INIT_AUTOMAKE(msgpack, 0.3.10)
+AM_INIT_AUTOMAKE(msgpack, 0.4.0)
 AC_CONFIG_HEADER(config.h)
 
 AC_SUBST(CFLAGS)