Here comes the Platform Update 1 for Microsoft .NET Framework 4 however a month ago, Microsoft released Visual Studio 2010 Service Pack 1. Undoubtedly to keep their technologies safe Microsoft releases security patches, but it is first time when Microsoft have targeted .NET Framework 4.

Microsoft .NET Framework 4 Platform Update 1 is a platform update that is a set of new features that provides additional functionality for top customer requests and important scenarios.

The features that are enabled in this update are:

Windows Workflow Foundation (WF)

• State machine workflows
  • New classes added: StateMachine, State, FinalState, Transition, StateMachineStateQuery, StateMachineStateRecord
  • Getting Started Tutorial: How to Create a State Machine Workflow
  • Windows Workflow Foundation (WF4) – Introduction to State Machine Hands On Lab
  • State Machine Activity Designers
  • State Machine Workflows
  • WF4 State Machine User Experience
• SqlWorkflowInstanceStore support for SQL Azure
  • The scripts that create the persistence database are modified to be compatible with Sql Azure
  • Retry semantics have been added and new error codes added that are specific to SQL Azure scenarios
  • For more information, see the More Information section of KB2478063
• CompensationExtension class, which enables custom workflow hosts to use WF4 compensation

The Microsoft .NET Platform Update 1 consists of three packages:

• Microsoft .NET Framework 4 Platform Update 1 (KB2478063) – This package contains the runtime files for the platform update. This package must be deployed on systems where applications that target the platform update are deployed.
• Multi-Targeting Pack for Microsoft .NET Framework 4 Platform Update 1 (KB2495638) – This package contains reference assemblies and intellisense files for the platform update. This package is installed as part of the next package.
• Microsoft .NET Framework 4 Platform Update 1 – Design-time Package for Visual Studio 2010 SP1 (KB2495593) – This package installs the previous two packages and configures Visual Studio 2010 SP1 with new .NET Framework targeting profiles, intellisense, and adds the state machine activities to the toolbox.

Source: MSDN Blog