diff --git a/Connect to OpenVPN over Shadowsocks.md b/Connect to OpenVPN over Shadowsocks.md
index 2b800f4..d3ecdad 100644
--- a/Connect to OpenVPN over Shadowsocks.md	
+++ b/Connect to OpenVPN over Shadowsocks.md	
@@ -9,4 +9,6 @@ Add these lines to your .ovpn file:
     socks-proxy 127.0.0.1 1080
     route SHADOWSOCKS_SERVER_IP 255.255.255.255 net_gateway
 
-Then connect OpenVPN.
\ No newline at end of file
+Then connect OpenVPN.
+
+Notice: only [versions that support UDP relay](https://github.com/clowwindy/shadowsocks/wiki/Feature-Comparison-across-Different-Versions) support this feature.
\ No newline at end of file