The PowerShell Team blog http://blogs.msdn.com/b/powershell/archive/2015/12/16/windows-management-framework-wmf-5-0-rtm-is-now-available.aspx
has been updated to show WMF is now available for
Windows 8.1
Windows 7 SP1
On the download center – https://www.microsoft.com/en-us/download/details.aspx?id=50395 –
You’ll see x86 versions of WMF 5.0 for Windows 8.1 and Windows 7
For the x64 versions you need to use the appropriate server version. For Windows 8.1 x64 use the Windows 2012 R2 download and for Windows 7 use the Windows 2008 R2 download.
Notice there isn’t any support for Windows 8. You’ll have to use the free upgrade to Windows 8.1
Windows 10 as of the November update is effectively at WMF 5.0 RTM version
under: PowerShell v5