This document lists the new features, enhancements, fixed issues and, removed or deprecated features for Hazelcast IMDG 3.12.10 release. The numbers in the square brackets refer to the issues in Hazelcast's GitHub repositories.

## Enhancements

* Added the support for checking duplicate fields when building
class definitions. [#17683]
* Enhanced the tracking of missing CP subsystem members after a
split-brain merge situation. [#17634]
* Added the missing validation checks to the client's connection retry
configuration. [#17570]
* Upgraded the versions of Hazelcast's snakeyaml-engine and Jackson
library dependencies to eliminate the denial of service vulnerabilities. [#17425], [#17444]
* Added timeout values for connect and read operations to the
Management Center service's task connection method. [#17387]

## Fixes

* Fixed an issue where Hazelcast was not releasing the acquired lock
sessions that fail for the reasons other than session expiration and
wait key cancellation. [#17701]
* Fixed an issue where the lock requests in clients' maps with
infinite time lease were returning `Long.MAX_VALUE`; now it returns `-1`. [#17680]
* Fixed an issue where Hazelcast was returning `false` if a client
is successfully deregistered from any member, but events are still
delivered for the non-deregistered ones. [#17648]
* Fixed the member side user code deployment; it was throwing an exception
when inner classes are used to be loaded. [#17579]
* Fixed an issue where the diagnostic plugins were not being rendered
properly when they fail. [#17500]
* Fixed an issue where the load balancer for clients
could not be configured declaratively. [#17228]
* Fixed a `NullPointerException` on the member startup when it
has Merkle tree configured and Hot Restart enabled. [#3825]
* Fixed an issue where a dynamically added WAN configuration
was not persistent after the member is restarted. [#3598]

##  Contributors

We would like to thank the contributors from our open source
community who worked on this release:

* [Marcin L](https://github.com/the-thing)
