diff --git a/doc/arm/notes.rst b/doc/arm/notes.rst
index 6446243051..edb9dea2c0 100644
--- a/doc/arm/notes.rst
+++ b/doc/arm/notes.rst
@@ -47,6 +47,7 @@ The list of known issues affecting the latest version in the 9.21 branch can be
 found at
 https://gitlab.isc.org/isc-projects/bind9/-/wikis/Known-Issues-in-BIND-9.21
 
+.. include:: ../notes/notes-9.21.5.rst
 .. include:: ../notes/notes-9.21.4.rst
 .. include:: ../notes/notes-9.21.3.rst
 .. include:: ../notes/notes-9.21.2.rst
diff --git a/doc/notes/notes-9.21.5.rst b/doc/notes/notes-9.21.5.rst
new file mode 100644
index 0000000000..dee2450d2e
--- /dev/null
+++ b/doc/notes/notes-9.21.5.rst
@@ -0,0 +1,96 @@
+.. 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 9.21.5
+---------------------
+
+New Features
+~~~~~~~~~~~~
+
+- Adds support for EDE code 1 and 2.
+
+  Add support for EDE codes 1 & 2 which might occurs during DNSSEC
+  validation in case of unsupported RRSIG algorithm or DNSKEY digest.
+  :gl:`#2715`
+
+- Add a rndc command to toggle jemalloc profiling.
+
+  The new command is `rndc memprof`. The memory profiling status is also
+  reported inside `rndc status`. The status also shows whether named can
+  toggle memory profiling or not and if the server is built with
+  jemalloc. :gl:`#4759`
+
+- Add support for multiple extended DNS errors.
+
+  Extended DNS error mechanism (EDE) may have several errors raised
+  during a DNS resolution. `named` is now able to add up to three EDE
+  codes in a DNS response. In the case of duplicate error codes, only
+  the first one will be part of the DNS response. :gl:`#5085`
+
+- Print the expiration time of the stale records.
+
+  Print the expiration time of the stale RRsets in the cache dump.
+
+Feature Changes
+~~~~~~~~~~~~~~~
+
+- Include destination address port number in query logging.
+
+  When query logging is enabled, named will now include the destination
+  address port in the logged message. :gl:`#5060`
+
+Bug Fixes
+~~~~~~~~~
+
+- Validate adb fetches.
+
+  ADB responses were not being validated, allowing spoofed responses to
+  be accepted and used for further lookups. This should not be possible
+  when the servers for the zone are in a signed zone, except with CD=1
+  requests or when glue is needed. This has been fixed. :gl:`#5066`
+
+- Recently expired records could be returned with timestamp in future.
+
+  Under rare circumstances, the RRSet that expired at the time of the
+  query could be returned with TTL far in the future.  This has been
+  fixed.
+
+  As a side-effect, the expiration time of expired RRSets are no longer
+  printed out in the cache dump. :gl:`#5094`
+
+- Yaml string not terminated in negative response in delv.
+
+  :gl:`#5098`
+
+- Fix a bug in dnssec-signzone related to keys being offline.
+
+  In the case when `dnssec-signzone` is called on an already signed
+  zone, and the private key file is unavailable, a signature that needs
+  to be refreshed may be dropped without being able to generate a
+  replacement. This has been fixed. :gl:`#5126`
+
+- Apply the memory limit only to ADB database items.
+
+  Resolver under heavy-load could exhaust the memory available for
+  storing the information in the Address Database (ADB) effectively
+  evicting already stored information in the ADB.  The memory used to
+  retrieve and provide information from the ADB is now not a subject of
+  the same memory limits that are applied for storing the information in
+  the Address Database. :gl:`#5127`
+
+- Avoid unnecessary locking in the zone/cache database.
+
+  Prevent lock contention among many worker threads referring to the
+  same database node at the same time.  This would improve zone and
+  cache database performance for the heavily contended database nodes.
+  :gl:`#5130`
+
+