docs: update CHANGELOG

Author: jpraynaud

CHANGELOG.md

@@ -11,6 +11,8 @@ As a minor extension, we have adopted a slightly different versioning convention
 
 - **BREAKING** changes in aggregator OpenAPI: removed the `next_cardano_transactions_signing_config` in `/epoch-settings` route.
 
+- Support for multiple aggregate signature proof systems.
+
 - Crates versions:
 
 | Crate | Version |

mithril-stm/CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.5.3 (10-07-2025)
+
+### Added
+
+- Added support for multiple aggregate signature proof systems.
+
 ## 0.5.0 (09-09-2025)
 
 ### Changed