# Introduced in 2.12.1

## Bug Fixes

* [GH-458](https://github.com/apache/mina-sshd/issues/458) Singleton thread pool for kex message handler flushing
* [SSHD-1338](https://issues.apache.org/jira/browse/SSHD-1338) Restore binary compatibility with 2.9.2

## New Features

## Behavioral changes and enhancements

## Potential compatibility issues

## Major Code Re-factoring

