6.4. Existing WF3 Users

WF has undergone some radical changes from version 3.0, which unfortunately means that those developers already utilizing WF3 are probably going to have to do some work to upgrade their applications.

6.4.1. Statemachine Workflow Has Gone

Probably the biggest problem you may encounter is that in the initial release of WF, there is no support for statemachine workflows. Microsoft seems undecided as to whether statemachine will be introduced in future versions of WF, but for now the answer is to utilize the new building blocks.

6.4.2. Upgraded Whitepapers

Microsoft has produced a number of excellent documents to assist you in upgrading to WF4, so your first step before you upgrade any applications should be to consult this link: http://go.microsoft.com/fwlink/?LinkID=153313.

6.4.3. WF3 Runtime

Version 3 of the WF runtime will be included with the .NET 4.0 runtime, so your WF3 should continue to run on the .NET 4.0 Framework.

6.4.4. Interop Activity

WF4 has a new activity called Interop (discussed later in this chapter) that can be used to run legacy WF code. This can serve as a halfway point until you are ready to upgrade your entire application.

6.4.5. Is It Worth the Upgrade?

Probably. WF4 lays the groundwork for future enhancements, and WF5 should not be such a radical upgrade. WF 4 offers superior performance (10 to 100 times quicker), a much-improved designer, and many other changes that I will discuss in this chapter.

Kenny Wolf (architect on the WCF and WF teams) at PDC 08 noted that some customers in the early adopter program reduced their code by 80 percent by moving to WF4.