diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5bd1fdc3..fe13be5d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,7 +21,7 @@
 
 cmake_minimum_required(VERSION 3.16)
 
-project(wolfMQTT VERSION 1.20.0 LANGUAGES C)
+project(wolfMQTT VERSION 1.21.0 LANGUAGES C)
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
 include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/functions.cmake)
diff --git a/ChangeLog.md b/ChangeLog.md
index f2ace152..229403e9 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,23 @@
 ## Release Notes
 
+### v1.21.0 (12/03/2025)
+Release 1.21.0 has been developed according to wolfSSL's development and QA
+process (see link below) and successfully passed the quality criteria.
+https://www.wolfssl.com/about/wolfssl-software-development-process-quality-assurance
+
+* Add port for NETX use by @JacobBarthelmeh in #427
+* Fix heap buffer overflow in MqttDecode_Num with bounds checking by @embhorn in #430
+* Restore instructions for testing against OQS mosquitto integration. by @anhu in #432
+* initial threadx test by @JacobBarthelmeh in #429
+* Rename ML-KEM hybrids to match IETF Draft. by @anhu in #435
+* Update expired test certs by @lealem47 in #441
+* Pin to ESP-IDF v5.5, limit workflow push branches, line endings by @gojimmypi in #444
+* Fix: MQTT v5 Property-Packet Protocol Validation and Decode Safety by @kaabia in #440
+* Fix: Correct state transition check in MqttClient_Auth by @kaabia in #439
+* fix: correct variable in MQTT property decode error checks by @kaabia in #445
+* Add fflush to mqtt-sub example by @embhorn in #447
+* Update license to GPLv3 by @embhorn in #448
+
 ### v1.20.0 (05/02/2025)
 Release 1.20.0 has been developed according to wolfSSL's development and QA
 process (see link below) and successfully passed the quality criteria.
diff --git a/configure.ac b/configure.ac
index b7925540..3a815ead 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@
 # All right reserved.
 
 AC_COPYRIGHT([Copyright (C) 2014-2025 wolfSSL Inc.])
-AC_INIT([wolfmqtt],[1.20.0],[https://github.com/wolfssl/wolfMQTT/issues],[wolfmqtt],[http://www.wolfssl.com])
+AC_INIT([wolfmqtt],[1.21.0],[https://github.com/wolfssl/wolfMQTT/issues],[wolfmqtt],[http://www.wolfssl.com])
 
 AC_PREREQ([2.63])
 AC_CONFIG_AUX_DIR([build-aux])
@@ -27,7 +27,7 @@ AC_ARG_PROGRAM
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_HEADERS([src/config.h])
 
-WOLFMQTT_LIBRARY_VERSION=18:0:0
+WOLFMQTT_LIBRARY_VERSION=18:1:0
 #                        | | |
 #                 +------+ | +---+
 #                 |        |     |
diff --git a/wolfmqtt/version.h b/wolfmqtt/version.h
index ecb57ea2..c91f46c8 100644
--- a/wolfmqtt/version.h
+++ b/wolfmqtt/version.h
@@ -34,8 +34,8 @@
 extern "C" {
 #endif
 
-#define LIBWOLFMQTT_VERSION_STRING "1.20.0"
-#define LIBWOLFMQTT_VERSION_HEX 0x01020000
+#define LIBWOLFMQTT_VERSION_STRING "1.21.0"
+#define LIBWOLFMQTT_VERSION_HEX 0x01021000
 
 #ifdef __cplusplus
 }