.NET 4.0 exams are there on the shelf. They have made plenty of changes to the .NET 4.0 and its exams as well. The main reason is .NET 4.0 has a CLR update and it is using a different version CLR. Normally there is no update from MCTS (old version) to MCTS (new version) the update exam available only for the MCPD holders. This is applicable to the .NET 4.0 also.

The .NET 4.0 has 4 MCTS versions and 3 MCPD versions.

MCTS Versions

• .NET 4.0 Windows Application Development (includes WPF and XAML)
• .NET 4.0 Web Application Development (includes Silverlight , MVC 2.0)
• .NET 4.0 Data Access Application Development (ADO.NET)
• .NET 4.0 Service Application Development (WCF)

MCPD Versions

• .NET 4.0 MCPD in Windows Development  ( Following MCTS are pre requisites : Windows Application,Data Access,WCF)
• .NET 4.0 MCPD in Web Development ( Following MCTS are pre requisites : Web Application,Data Access,WCF)
• .NET 4.0 MCPD Enterprise Application Development ( Following MCTS are pre requisites : Windows Application,Web Application,Data Access,WCF)

There’s no separate exams for WPF, WF in .NET 4.0. But they may arrive very soon. I think MCTS for WF will definitely arrive with the SharePoint 2010 exams.