diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 7e91838de53d..d72052b16044 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -4825,11 +4825,14 @@ pref("network.tcp.keepalive.retry_interval", 1); // seconds
 pref("network.tcp.keepalive.probe_count", 4);
 #endif
 
-#if defined(XP_WIN) || defined(XP_MACOSX)
+#if !defined(EARLY_BETA_OR_EARLIER)
+pref("network.tcp.tcp_fastopen_enable", false);
+#elif  defined(XP_WIN) || defined(XP_MACOSX)
 pref("network.tcp.tcp_fastopen_enable", true);
 #else
 pref("network.tcp.tcp_fastopen_enable", false);
 #endif
+
 pref("network.tcp.tcp_fastopen_consecutive_failure_limit", 5);
 // We are trying to detect stalled tcp connections that use TFO and TLS
 // (bug 1395494).