The February CTP for WinFX came out just the other day. And the news for worflow afficionados is that the Windows Workflow Foundation build is the same as in the January CTP for WinFX. The Windows Workflow Foundation build is known as Beta 2 and is number 3.0.3603.4. You can check this build number by using explorer to open c:\Windows\Assembly. Right click on System.Workflow.Activities and choose Properties. Click the Version tab and check the File Version.