The information in this post is out of date.
Visit msdn.com/data/ef for the latest information on current and past releases of EF.
We then shipped a Beta and a Release Candidate of EF 4.2. Today we are making the final release of EF 4.2 available.
EF 4.2 = Bug Fixes + Semantic Versioning
When we released ‘EF 4.1 Update 1’ we introduced a bug that affects third party EF providers using a generic class for their provider factory implementation, things such as WrappingProviderFactory<TProvider>. We missed this during our testing and it was reported by some of our provider writers after we had shipped. If you hit this bug you will get a FileLoadException stating “The given assembly name or codebase was invalid”. This bug is blocking some third party providers from working with ‘EF 4.1 Update 1’ and the only workaround for folks using an affected provider is to ask them to remain on EF 4.1. Third party provider writers then identified some areas in EF where it was hard to get EF to work with their providers, so we decided to address these issues in the EF 4.2 release. These provider related changes will be the only changes between ‘EF 4.1 Update 1’ and ‘EF 4.2’.
Obviously a single bug fix wouldn’t normally warrant bumping the minor version, but we also wanted to take the opportunity to get onto the semantic versioning path rather than calling the release ‘EF 4.1 Update 2’.
The following walkthroughs are available for EF 4.2:
Getting EF 4.2
Code First Migrations
To use Code First Migrations with EF 4.2 you will need to upgrade to the latest version of the EntityFramework.Migrations NuGet package.
Failure to update to the latest version of Code First Migrations will result in an error stating “Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.“
After updating to the latest Code First Migrations package you will need to close and re-open Visual Studio.
Model First & Database First Templates
The templates for using the DbContext API with Model First and Database First are now available under the “Online Templates” tab when “Right-Click –> Add Code Generation Item…” is selected on the EF Designer.
This release can be used in a live operating environment subject to the terms in the license terms. The ADO.NET Entity Framework Forum can be used for questions relating to this release.
What’s Not in This Release?
As covered earlier this release is just a small update to the DbContext & Code First runtime. The features that were included in EF June 2011 CTP require changes to the Core Entity Framework Libraries that are part of the .NET Framework and will ship at a later date.
Our Code First Migrations work is continuing and we are working to get the next release in your hands soon.
ADO.NET Entity Framework Team