# Upgrading from Amazon S3 to API-based integration
<a name="upgrade-crm-api"></a>

**Note**  
The topics in this section assume you've completed the prerequisites for an AWS Partner Central integration, an AWS Marketplace integration, or both. For more information, refer to [Integration prerequisites](crm-integration-setting-up.md) and [Getting started](crm-integration-getting-started.md) earlier in this guide.

This section walks you through upgrading your AWS Partner CRM Connector from Amazon S3-based to API-based integration. The migration involves three main phases:

1. **Complete prerequisites** – The Alliance Lead performs actions within Partner Central.

1. **Set up AWS infrastructure** – The IT Cloud Admin and the Salesforce Administrator perform activities in the AWS Management Console and in Salesforce to enable the API-based integration.

1. **Finalize setup and configuration within Salesforce** – The Salesforce Administrator finishes the configuration and setup within Salesforce.

**Note**  
We recommend that you complete these activities in a Sandbox environment first, test thoroughly, and then deploy to Production.

**Topics**
+ [Complete prerequisites](upgrade-phase1-prerequisites.md)
+ [Set up AWS infrastructure](upgrade-phase2-aws-infrastructure.md)
+ [Finalize setup and configuration within Salesforce](upgrade-phase3-salesforce-config.md)