diff --git a/include/sxmp/sxmp.h b/include/sxmp/sxmp.h
index 7dea8ef..41d9eba 100644
--- a/include/sxmp/sxmp.h
+++ b/include/sxmp/sxmp.h
@@ -28,6 +28,7 @@
 #include <sexpr/faststack.h>
 
 #include <sxmp/errno.h>
+#include <sxmp/version.h>
 
 #define VERIFY_DEPTH  1  /* FIXME: */
 
diff --git a/include/sxmp/version.h b/include/sxmp/version.h
new file mode 100644
index 0000000..9963531
--- /dev/null
+++ b/include/sxmp/version.h
@@ -0,0 +1,22 @@
+/*
+ * Secure X Message Passing Library v2 implementation.
+ * (sxmplv2) it superseed all versions before due to the:
+ * - memory consumption
+ * - new features such as pulse emitting
+ * - performance optimization
+ *
+ * This is a proprietary software. See COPYING for further details.
+ *
+ * (c) Askele Group 2013-2015 <http://askele.com>
+ *
+ */
+
+#ifndef __SXMP_VERSION_H__
+#define	__SXMP_VERSION_H__
+
+#define SXMP_BRANCH  0
+#define SXMP_MAJOR   4
+#define SXMP_MINOR   1
+
+#endif /* __SXMP_VERSION_H__ */
+