diff --git a/CMakeLists.txt b/CMakeLists.txt
index b65f55a4..7088b1ad 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,7 @@ list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake_modules/)
 
 set(TRANTOR_MAJOR_VERSION 1)
 set(TRANTOR_MINOR_VERSION 5)
-set(TRANTOR_PATCH_VERSION 20)
+set(TRANTOR_PATCH_VERSION 21)
 set(TRANTOR_VERSION ${TRANTOR_MAJOR_VERSION}.${TRANTOR_MINOR_VERSION}.${TRANTOR_PATCH_VERSION})
 
 include(GNUInstallDirs)
diff --git a/ChangeLog.md b/ChangeLog.md
index c7581358..4fc0f80d 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -4,6 +4,16 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+## [1.5.21] - 2024-09-10
+
+### API changes list
+
+- Add a method to reload the SSL certificate and private key on the fly.
+
+### Changed
+
+- Keep log level consistency.
+
 ## [1.5.20] - 2024-07-20
 
 ### Changed
@@ -668,7 +678,9 @@ All notable changes to this project will be documented in this file.
 
 ## [1.0.0-rc1] - 2019-06-11
 
-[Unreleased]: https://github.com/an-tao/trantor/compare/v1.5.20...HEAD
+[Unreleased]: https://github.com/an-tao/trantor/compare/v1.5.21...HEAD
+
+[1.5.21]: https://github.com/an-tao/trantor/compare/v1.5.20...v1.5.21
 
 [1.5.20]: https://github.com/an-tao/trantor/compare/v1.5.19...v1.5.20