Update CHANGELOG

services/horizon/CHANGELOG.md

@@ -3,12 +3,25 @@
 All notable changes to this project will be documented in this
 file. This project adheres to [Semantic Versioning](http://semver.org/).
 
-## Unreleased
+## 2.31.0
 
 ### Breaking Changes
 
 - Change ingestion filtering logic to store transactions if any filter matches on it. ([5303](https://github.com/stellar/go/pull/5303))
-  - The previous behaviour was to store a tx only if both asset and account filters match together. So even if a tx matched an account filter but failed to match an asset filter, it would not be stored by Horizon.  
+  - The previous behaviour was to store a tx only if both asset and account filters match together. So even if a tx matched an account filter but failed to match an asset filter, it would not be stored by Horizon.
+
+### Added
+
+- Bump XDR definitions ([5289](https://github.com/stellar/go/pull/5289)), ([5330](https://github.com/stellar/go/pull/5330))
+- Add new async transaction submission endpoint ([5188](https://github.com/stellar/go/pull/5188))
+- Add `horizon_ingest_errors_total` metric key ([5302](https://github.com/stellar/go/pull/5302))
+- Add transaction hash to txsub timeout response ([5328](https://github.com/stellar/go/pull/5328))
+
+### Fixed
+
+- Clean up duplicate captive-core default config files ([5293](https://github.com/stellar/go/pull/5293))
+- Remove internal API reference in the docs ([5336](https://github.com/stellar/go/pull/5336))
+- Updated documentation guide for developers ([5337](https://github.com/stellar/go/pull/5337))
 
 ## 2.30.0