--- /dev/null
+.. Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+..
+.. SPDX-License-Identifier: MPL-2.0
+..
+.. This Source Code Form is subject to the terms of the Mozilla Public
+.. License, v. 2.0. If a copy of the MPL was not distributed with this
+.. file, you can obtain one at https://mozilla.org/MPL/2.0/.
+..
+.. See the COPYRIGHT file distributed with this work for additional
+.. information regarding copyright ownership.
+
+Notes for BIND 9.20.10
+----------------------
+
+New Features
+~~~~~~~~~~~~
+
+- Implement a new 'notify-defer' configuration option.
+
+ This new option sets a delay (in seconds) to wait before sending a set
+ of NOTIFY messages for a zone. Whenever a NOTIFY message is ready to
+ be sent, sending will be deferred for this duration. This option is
+ not to be confused with the :any:`notify-delay` option. The default is
+ 0 seconds. :gl:`#5259`
+
+Removed Features
+~~~~~~~~~~~~~~~~
+
+- Implement the systemd notification protocol manually to remove
+ dependency on libsystemd.
+
+ libsystemd, despite being useful, adds a huge surface area for just
+ using the sd_notify API. libsystemd's surface has been exploited in
+ the past [1].
+
+ Implement the systemd notification protocol by hand since it is just
+ sending newline-delimited datagrams to a UNIX socket. The code
+ shouldn't need more attention in the future since the notification
+ protocol is covered under systemd's stability promise [2].
+
+ We don't need to support VSOCK-backed service notifications since they
+ are only intended for virtual machine inits.
+
+ [1]: https://www.openwall.com/lists/oss-security/2024/03/29/4 [2]:
+ https://systemd.io/PORTABILITY_AND_STABILITY/
+
+Bug Fixes
+~~~~~~~~~
+
+- Fix zone deletion issue.
+
+ A secondary zone could initiate a new zone transfer from the primary
+ server after it had been already deleted from the secondary server,
+ and before the internal garbage collection was activated to clean it
+ up completely. This has been fixed. :gl:`#5291`
+
+- Fix a zone refresh bug.
+
+ A secondary zone could fail to further refresh with new versions of
+ the zone from a primary server if named was reconfigured during the
+ SOA request step of an ongoing zone transfer. This has been fixed.
+ :gl:`#5307`
+
+