--- dhcp-options.5.orig	2020-04-13 17:07:01 UTC
+++ dhcp-options.5
@@ -346,6 +346,10 @@ This option specifies whether the client should config
 for packet forwarding.
 A value of 0 means disable IP forwarding, and a value of 1 means enable
 IP forwarding.
+.It Ic option ipv6-only-preferred Ar uint32 ;
+The number of seconds for which an IPv6-only-capable client should disable
+DHCPv4.
+See RFC 8925 for details.
 .It Ic option irc-server Ar ip-address Oo , Ar ip-address ... Oc ;
 The
 .Ic irc-server