# Release: AWS IoT Greengrass Core v2.5.2 software update on December 3, 2021
AWS IoT Greengrass Core v2.5.2 software updateAWS IoT Greengrass Core v2.5.2 software update[https://docs.aws.amazon.com/greengrass/v2/developerguide/greengrass-release-2021-12-03.html](https://docs.aws.amazon.com/greengrass/v2/developerguide/greengrass-release-2021-12-03.html)

This release provides version 2.5.2 of the Greengrass nucleus component and updates AWS-provided components. It fixes an issue with the Windows service that occurs after the Greengrass nucleus updates. It also includes support for the AWS IoT Device Defender component on Windows devices.

This release provides version 2.5.2 of the Greengrass nucleus component.

**Release date:** December 3, 2021

**Topics**
+ [

## Public component updates
](#greengrass-2021-12-03-components)

## Public component updates


The following table lists AWS-provided components that include new and updated features.

**Important**  <a name="component-patch-update-note"></a>
<a name="component-patch-update"></a>When you deploy a component, AWS IoT Greengrass installs the latest supported versions of all of that component's dependencies. Because of this, new patch versions of AWS-provided public components might be automatically deployed to your core devices if you add new devices to a thing group, or you update the deployment that targets those devices. Some automatic updates, such as a nucleus update, can cause your devices to restart unexpectedly.   
<a name="component-version-pinning"></a>To prevent unintended updates for a component that is running on your device, we recommend that you directly include your preferred version of that component when you [create a deployment](create-deployments.md). For more information about update behavior for AWS IoT Greengrass Core software, see [Update the AWS IoT Greengrass Core software (OTA)](update-greengrass-core-v2.md).


| **Component** | **Details** | 
| --- | --- | 
| Greengrass nucleus |  Version 2.5.2 of the [Greengrass nucleus](greengrass-nucleus-component.md) is available. <a name="changelog-nucleus-2.5.2"></a>[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/greengrass/v2/developerguide/greengrass-release-2021-12-03.html)  | 
| AWS IoT Device Defender |  Version 3.0.1 of the [AWS IoT Device Defender](device-defender-component.md) component is available. <a name="changelog-device-defender-3.0.0-major-version-changes"></a>This version of the AWS IoT Device Defender component expects different configuration parameters than version 2.x. If you use a non-default configuration for version 2.x, and you want to upgrade from v2.x to v3.x, you must update the component's configuration. For more information, see [AWS IoT Device Defender component configuration](device-defender-component.md#device-defender-component-configuration). <a name="changelog-device-defender-3.0.1"></a>[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/greengrass/v2/developerguide/greengrass-release-2021-12-03.html)  |