The Amazon SDK for .NET V3 has entered maintenance mode.

We recommend that you migrate to [Amazon SDK for .NET V4](https://docs.amazonaws.cn/sdk-for-net/v4/developer-guide/welcome.html). For additional details and information on how to migrate, please refer to our [maintenance mode announcement](https://aws.amazon.com/blogs/developer/aws-sdk-for-net-v3-maintenance-mode-announcement/).

# Document history
Amazon OpsWorks

Amazon OpsWorks has reached End of Life. It has been removed from the documentation.Included more IAM best practices updates

Updated guide to align with the IAM best practices. For more information, see [Security best practices in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html).IAM best practices updates

Updated guide to align with the IAM best practices. For more information, see [Security best practices in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html).Amazon SDK for .NET version 3 guide consolidation

The two Amazon SDK for .NET version 3 developer guides, "V3" and "latest", have been consolidated into one guide under the "v3" URL.Enabling SDK Metrics

Removed information about enabling SDK metrics, which has been deprecated.Retiring EC2-Classic

Added notes about retiring EC2-Classic.Table of contents

Updated table of contents to make code examples more easily discoverable.

The following table describes the important changes since the last release of the *Amazon SDK for .NET Developer Guide*. For notification about updates to this documentation, you can subscribe to an [RSS feed](https://docs.amazonaws.cn/sdk-for-net/v3/developer-guide/amazon-aws-sdk-for-net-dev-guide-doc-history.rss).

| Change | Description | Date | 
| --- |--- |--- |
| [What's new](whats-new.md) | Added a note about version 2.0 of the Amazon Deploy Tool for .NET CLI. | October 17, 2025 | 
| [Amazon OpsWorks](#document-history) | Amazon OpsWorks has reached End of Life. It has been removed from the documentation. | September 16, 2025 | 
| [What's new](whats-new.md) | End-of-support has been announced for V3 of the Amazon SDK for .NET. | August 21, 2025 | 
| [Message Processing Framework](msg-proc-fw.md) | The Amazon Message Processing Framework for .NET has reached general availability\$1 | May 5, 2025 | 
| [What's new](whats-new.md) | Version 4 of the Amazon SDK for .NET is generally available\$1 For more information, see the [Amazon SDK for .NET (V4) Developer Guide](https://docs.amazonaws.cn/sdk-for-net/v4/developer-guide/welcome.html), especially the topic for [Migrating to version 4](https://docs.amazonaws.cn/sdk-for-net/v4/developer-guide/net-dg-v4.html). | April 28, 2025 | 
| [Retries and timeouts](retries-timeouts.md) | Included information about per-method timeouts using `CancellationToken` for asynchronous method calls. | April 9, 2025 | 
| [Integrating Amazon with .NET Aspire in the Amazon SDK for .NET](aspire-integrations.md) | Included information about how Amazon has been Integrated with .NET Aspire in the Amazon SDK for .NET. | February 15, 2025 | 
| [Observability](observability.md) | Announced the GA release for observability | February 10, 2025 | 
| [What's new](whats-new.md) | Added information about new default behavior for integrity protection. | January 15, 2025 | 
| [S3 Encryption Client V4 Migration](s3-encryption-migration-v2-v4.md) | Added information about migrating from V2 to V4. | December 9, 2024 | 
| [What's new](whats-new.md) | Added information about the fourth preview release of the Amazon SDK for .NET version 4. | November 15, 2024 | 
| [Observability](observability.md) | Added preview information about observability in the Amazon SDK for .NET, which enables the gathering of telemetry data. | September 13, 2024 | 
| [API reference for the Amazon SDK for .NET](sdk-api-ref.md) | The Amazon SDK for .NET API references for V1 and V2 have been deprecated. Information has been included about this deprecation and how to obtain and view the deprecated references. | September 4, 2024 | 
| [What's new](whats-new.md) | Added information about the first preview release of the Amazon SDK for .NET version 4. | August 16, 2024 | 
| [What's new](whats-new.md) | Updated information about upcoming changes to .NET Framework support. | June 20, 2024 | 
| [What's new](whats-new.md) | Added information about the preview release of the Amazon Message Processing Framework for .NET | March 28, 2024 | 
| [What's new](whats-new.md) | Included information about support for .NET 8. | February 23, 2024 | 
| [What's new](whats-new.md) | Included information about upcoming changes to .NET Framework support. | February 18, 2024 | 
| [Obtaining AWSSDK assemblies](net-dg-obtain-assemblies.md) | Included information about assemblies that support .NET 8 and later. | January 8, 2024 | 
| [Amazon Message Processing Framework for .NET](msg-proc-fw.md) | Included information about the Beta release of the Message Processing Framework. | December 10, 2023 | 
| [Using Amazon DynamoDB NoSQL databases](dynamodb-intro.md) | Updated information about the document and object persistence programming models. It is now possible to prevent certain latency or deadlock conditions due to cold-start and thread-pool behaviors. | November 15, 2023 | 
| [Included more IAM best practices updates](#document-history) | Updated guide to align with the IAM best practices. For more information, see [Security best practices in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html). | October 5, 2023 | 
| [Obtaining AWSSDK assemblies](net-dg-obtain-assemblies.md) | Removed information about installing the Amazon SDK for .NET by using Amazon Tools for Windows installer (that is, the MSI), which has been deprecated. | September 25, 2023 | 
| [IAM best practices updates](#document-history) | Updated guide to align with the IAM best practices. For more information, see [Security best practices in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html). | July 18, 2023 | 
| [Lambda Annotations](aws-lambda-annotations.md) | The Amazon Lambda Annotations framework has been released for general availability. | July 17, 2023 | 
| [What's new](whats-new.md) | Added information about the preview release of the Distributed Cache Provider for DynamoDB. | July 15, 2023 | 
| [Table of contents](#document-history) | Updated table of contents to make code examples more easily discoverable. | June 8, 2023 | 
| [Region resolution](net-dg-region-selection.md) | Added information about how the SDK resolves a missing Region specification. | March 14, 2023 | 
| [Support for the MSI](net-dg-obtain-assemblies.md) | Added note about ending support for the Amazon Tools for Windows installer. | March 6, 2023 | 
| [Lambda Annotations (Preview)](aws-lambda-annotations.md) | Preview of the Amazon Lambda Annotations framework. | September 22, 2022 | 
| [Deploy applications to Amazon](deploying.md) | Moved main content to a GitHub Pages site: https://aws.github.io/aws-dotnet-deploy/ | June 28, 2022 | 
| [Retiring EC2-Classic](#document-history) | Added notes about retiring EC2-Classic. | April 13, 2022 | 
| [Single sign-on with the Amazon SDK for .NET](sso.md) | Added information about single sign-on (SSO) when using the Amazon SDK for .NET. | March 17, 2022 | 
| [Enforcing a minimum TLS version](enforcing-tls.md) | Added information about TLS 1.3. | March 16, 2022 | 
| [Work with Amazon services](working-with-aws-services.md) | Included lists of the code examples that are available on GitHub. | February 28, 2022 | 
| [Enabling SDK Metrics](#document-history) | Removed information about enabling SDK metrics, which has been deprecated. | January 20, 2022 | 
| [Deploy applications to Amazon](deploying.md) | Added a reference to the Amazon Toolkit for Visual Studio, which provides deployment functionality that is similar to the Amazon Deploy Tool. | October 26, 2021 | 
| [Amazon SDK for .NET version 3 guide consolidation](#document-history) | The two Amazon SDK for .NET version 3 developer guides, "V3" and "latest", have been consolidated into one guide under the "v3" URL. | August 18, 2021 | 
| [Migrating from .NET Standard 1.3](migration-from-net-standard-1-3.md) | Support for .NET Standard 1.3 on the Amazon SDK for .NET has come to its end of life. | March 25, 2021 | 
| [Deploy applications to Amazon (preview)](deploying.md) | Added preview information about the Amazon Deploy Tool, which you can use to deploy an application from the .NET CLI. | March 15, 2021 | 
| [Version 3.5 of the Amazon SDK for .NET](net-dg-v35.md) | Version 3.5 of the Amazon SDK for .NET has been released. | August 25, 2020 | 
| [Paginators](paginators.md) | Added paginators to many service clients, which make pagination of API results more convenient. | August 24, 2020 | 
| [Retries and timeouts](retries-timeouts.md) | Added information about retry modes. | August 20, 2020 | 
| [Using KMS keys for S3 encryption](kms-keys-s3-encryption.md) | Updated example to use version 2 of the S3 encryption client. | August 6, 2020 | 
| [Migrating from .NET Standard 1.3](migration-from-net-standard-1-3.md) | Added information about ending support for .NET Standard 1.3 at the end of 2020. | May 18, 2020 | 
| [Quick start](quick-start.md) | Added a quick-start section with basic setup and tutorials to introduce the reader to the Amazon SDK for .NET. | March 27, 2020 | 
| [Enforcing TLS 1.2](enforcing-tls.md) | Added information about how to enforce TLS 1.2 in the SDK. | March 10, 2020 |