diff --git a/src/wps/wps_attr_build.c b/src/wps/wps_attr_build.c
index f10f3c8da..3ec8204cc 100644
--- a/src/wps/wps_attr_build.c
+++ b/src/wps/wps_attr_build.c
@@ -178,6 +178,13 @@ int wps_build_version2(struct wpabuf *msg)
 	wpabuf_put_be16(msg, ATTR_VERSION2);
 	wpabuf_put_be16(msg, 1);
 	wpabuf_put_u8(msg, WPS_VERSION);
+#ifdef CONFIG_WPS_EXTENSIBILITY_TESTING
+	wpa_printf(MSG_DEBUG, "WPS:  * Extensibility Testing - extra "
+		   "attribute";
+	wpabuf_put_be16(msg, ATTR_EXTENSIBILITY_TEST);
+	wpabuf_put_be16(msg, 1);
+	wpabuf_put_u8(msg, 42);
+#endif /* CONFIG_WPS_EXTENSIBILITY_TESTING */
 	return 0;
 }
 
diff --git a/src/wps/wps_defs.h b/src/wps/wps_defs.h
index 197d20c7a..13716de9d 100644
--- a/src/wps/wps_defs.h
+++ b/src/wps/wps_defs.h
@@ -15,7 +15,11 @@
 #ifndef WPS_DEFS_H
 #define WPS_DEFS_H
 
+#ifdef CONFIG_WPS_EXTENSIBILITY_TESTING
+#define WPS_VERSION 0x57
+#else /* CONFIG_WPS_EXTENSIBILITY_TESTING */
 #define WPS_VERSION 0x20
+#endif /* CONFIG_WPS_EXTENSIBILITY_TESTING */
 
 /* Diffie-Hellman 1536-bit MODP Group; RFC 3526, Group 5 */
 #define WPS_DH_GROUP 5
@@ -130,7 +134,8 @@ enum wps_attribute {
 	ATTR_VERSION2 = 0x1067,
 	ATTR_REQUEST_TO_ENROLL = 0x1068,
 	ATTR_AUTHORIZED_MACS = 0x1069,
-	ATTR_REQUESTED_DEV_TYPE = 0x106a
+	ATTR_REQUESTED_DEV_TYPE = 0x106a,
+	ATTR_EXTENSIBILITY_TEST = 0x10fa /* _NOT_ defined in the spec */
 };
 
 /* Device Password ID */