The Release Candidate for Entity Framework 6 is now available for download, with improvements including Async language support, multi-tenant migrations, and support for custom Code First conventions.

This is the first open source version of EF6 being developed in CodePlex, and it represents a major upgrade from EF5.

The custom convention support means you can now write custom conventions for Code First to help avoid repetitive configuration. There’s a simple API for lightweight conventions, along with some more complex building blocks that will let developers write more complicated conventions. You can view a walkthrough of both options on MSDN's Data Developer Center.

Async Query and Save means EF6 now supports the new simplified approach to asynchronous programming introduced in Visual Studio 2012 and .NET 4.5. The simplified approach means the compiler handles the management of the asynchronous elements, and your app retains a simpler logical structure that resembles synchronous code. EF6 supports the task-based asynchronous patterns such as SaveChanges and LINQ methods that execute queries such as First and ToList. There’s a walkthrough of the feature on MSDN's Data Developer Center.

The addition of multiple contexts per database (formerly known as 'multi-tenant migrations') overcomes the limitation in previous versions of EF where you were limited to one Code First model per database when using Migrations or when Code First automatically created the database for you. This limitation is now removed.

Other improvements include support for code-based configuration rather than using a config file; dependency resolution has added support for the Service Locator pattern; and support for enums and spatial data types. This support has been added by moving the core components that used to be in the .NET Framework into the EF NuGet package, which also means you can benefit from the performance improvements from EF5 on .NET 4.0.

The release candidate is feature complete, and the final release of EF6 will be made available at the same time as Visual Studio 2013 later this year. The runtime is available on NuGet and the tooling for Visual Studio 2012 is available on the Microsoft Download Center.