Index: man-pages-6.05.01/man7/tcp.7
===================================================================
--- man-pages-6.05.01.orig/man7/tcp.7
+++ man-pages-6.05.01/man7/tcp.7
@@ -486,9 +486,31 @@ When enabled, outgoing ECN-setup SYNs th
 normal SYN retransmission timeout will be resent with CWR and
 ECE cleared.
 .TP
-.IR tcp_fack " (Boolean; default: enabled; since Linux 2.2)"
+.IR tcp_fack " (integer; default: see below; since Linux 2.2)"
 .\" Since Linux 2.1.92
 Enable TCP Forward Acknowledgement support.
+
+Prior to Linux 4.11, this option was enabled by default.
+In Linux 4.11, it was disabled by default in favor of RACK (see
+tcp_recovery).
+In Linux 4.15 it was deprecated entirely and its value is ignored.
+.TP
+.IR tcp_recovery " (integer; default: 0x1; since Linux 4.4)"
+Enable various experimental loss recovery features.
+
+This field is a bitmap to enable various loss recovery features.
+.RS
+.IP 0x1
+enables the RACK loss detection for fast detection of lost
+retransmissions and tail drops. It also subsumes and disables
+RFC6675 recovery for SACK connections. (Since Linux 4.4)
+.IP 0x2
+makes RACK's reordering window static (min_rtt/4). (Since
+Linux 4.15)
+.IP 0x4
+disables RACK's DUPACK threshold heuristic (Since Linux
+4.18).
+.RE
 .TP
 .IR tcp_fin_timeout " (integer; default: 60; since Linux 2.2)"
 .\" Since Linux 2.1.53