If you haven’t noticed already, Microsoft has had a very quick turnaround of versions of PowerShell. We started back with Windows PowerShell v.1.0 and not long afterwards Windows PowerShell v. 2.0 was released. With the release of Windows 8 and Windows Server 2012, PowerShell v. 3.0 was released.
Now, with the release of Windows 8.1 and Windows Server 2012 R2, Windows PowerShell v. 4.0 is now on the way!!
You can download a preview version of Windows PowerShell v. 4.0 here: http://www.microsoft.com/en-us/download/details.aspx?id=39347
If you want to start playing around with the RTM release of Windows PowerShell v. 4.0, you can download the RTM releases of Windows 8.1 or Windows Server 2012 R2 from MSDN Subscriptions: http://msdn.microsoft.com/subscriptions