diff --git a/user.js b/user.js
index 4cae9bd..3010a18 100644
--- a/user.js
+++ b/user.js
@@ -473,6 +473,7 @@ user_pref("network.dns.disableIPv6", true);
 user_pref("network.http.spdy.enabled", false);
 user_pref("network.http.spdy.enabled.deps", false);
 user_pref("network.http.spdy.enabled.http2", false);
+user_pref("network.http.spdy.websockets", false); // [FF65+]
 /* 0703: disable HTTP Alternative Services [FF37+]
  * [SETUP-PERF] Relax this if you have FPI enabled (see 4000) *AND* you understand the
  * consequences. FPI isolates these, but it was designed with the Tor protocol in mind,