--- a/plugins/mod_websocket.lua	Wed Mar 23 12:17:28 2016 +0000
+++ b/plugins/mod_websocket.lua	Wed Mar 23 14:31:35 2016 +0100
@@ -226,8 +226,7 @@
 			frame.opcode = 0xA;
 			conn:write(build_frame(frame));
 			return "";
-		elseif opcode == 0xA then -- Pong frame
-			module:log("warn", "Received unexpected pong frame: " .. tostring(frame.data));
+		elseif opcode == 0xA then -- Pong frame, MAY be sent unsolicited, eg as keepalive
 			return "";
 		else
 			log("warn", "Received frame with unsupported opcode %i", opcode);