diff -uNr ttyd-1.6.1/src/server.c ttyd-1.6.1.mod/src/server.c
--- ttyd-1.6.1/src/server.c	2020-06-26 08:07:38.000000000 +0300
+++ ttyd-1.6.1.mod/src/server.c	2020-10-01 12:48:37.004505774 +0300
@@ -449,9 +449,6 @@
           LWS_LIBRARY_VERSION);
   info.server_string = server_hdr;
 #endif
-#if LWS_LIBRARY_VERSION_NUMBER >= 2001000
-  info.ws_ping_pong_interval = 5;
-#endif
 
   if (strlen(iface) > 0) {
     info.iface = iface;
