Which version of the .net framework will Sharepoint 2010 use?

Now that the Sharepoint conference has started and at least some of the NDA开发者_运维问答 restrictions have been lifted.

I was wondering which version for the .net framework Sharepoint 2010 will use. Am especially interested in if Sharepoint workflow is built on the workflow in .net 4.0. Since we have had problems with performance in workflow for .net 3.5.

It uses .NET 3.5

Apparently the release timeframes didn't work out to get SharePoint 2010 working with .NET Framework 4.0.

Have a look here