# Release: Amazon IoT Greengrass Core v2.4.0 software update on August 3, 2021
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This release provides version 2.4.0 of the Greengrass nucleus component, new Amazon-provided components, and updates to Amazon-provided components.

**Release date:** August 3, 2021

**Release highlights**
+ **System resource limits**—The Greengrass nucleus component now supports system resource limits. You can configure the maximum amount of CPU and RAM usage that each component's processes can use on the core device. For more information, see [Configure system resource limits for components](configure-greengrass-core-v2.md#configure-component-system-resource-limits).
+ **Pause/resume components**—The Greengrass nucleus now supports pausing and resuming components. You can use the interprocess communication (IPC) library to develop custom components that pause and resume other components' processes. For more information, see [PauseComponent](ipc-component-lifecycle.md#ipc-operation-pausecomponent) and [ResumeComponent](ipc-component-lifecycle.md#ipc-operation-resumecomponent).
+ **Install with Amazon IoT fleet provisioning**—Use the new Amazon IoT fleet provisioning plugin to install the Amazon IoT Greengrass Core software on devices that connect to Amazon IoT to provision required Amazon resources. Devices use a claim certificate to provision. You can embed the claim certificate on devices during manufacturing, so each device can provision as soon as it comes online. For more information, see [Install Amazon IoT Greengrass Core software with Amazon IoT fleet provisioning](fleet-provisioning.md).
+ **Install with custom provisioning**—Develop a custom provisioning plugin to provision required Amazon resources when you install the Amazon IoT Greengrass Core software on devices. You can create a Java application that runs during installation to set up Greengrass core devices for your custom use case. For more information, see [Install Amazon IoT Greengrass Core software with custom resource provisioning](custom-provisioning.md).

**Topics**
+ [Public component updates](#greengrass-2021-08-03-components)

## Public component updates
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The following table lists Amazon-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, Amazon IoT Greengrass installs the latest supported versions of all of that component's dependencies. Because of this, new patch versions of Amazon-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 Amazon IoT Greengrass Core software, see [Update the Amazon IoT Greengrass Core software (OTA)](update-greengrass-core-v2.md).


| **Component** | **Details** | 
| --- | --- | 
| Greengrass nucleus | Version 2.4.0 of the [Greengrass nucleus](greengrass-nucleus-component.md) is available.<a name="changelog-nucleus-2.4.0"></a>[See the AWS documentation website for more details](http://docs.amazonaws.cn/en_us/greengrass/v2/developerguide/greengrass-release-2021-08-03.html) | 
| Greengrass CLI | Version 2.4.0 of the [Greengrass CLI](greengrass-cli-component.md) is available.<a name="changelog-greengrass-cli-2.4.0"></a>[See the AWS documentation website for more details](http://docs.amazonaws.cn/en_us/greengrass/v2/developerguide/greengrass-release-2021-08-03.html) | 
| Amazon IoT fleet provisioning by claim | The Amazon IoT fleet provisioning by claim plugin is now available. For more information, see [Install Amazon IoT Greengrass Core software with Amazon IoT fleet provisioning](fleet-provisioning.md).[See the AWS documentation website for more details](http://docs.amazonaws.cn/en_us/greengrass/v2/developerguide/greengrass-release-2021-08-03.html) |