When Windows Server 2016 ships, Microsoft will release WMF 5.1, which includes all the changes and responses to your feedback that have been made since WMF 5.0 shipped.
Many of these improvements are currently included in the Windows 10 Insider Builds.
WMF 5.1 will be supported on the same systems WMF 5.0 supports, and will install directly over WMF 5.0 if it is present. It is important to note that WMF 5.1 will be required for long-term support of the WMF 5 features. We will continue to support WMF 5.0 for critical security issues for 4 months after WMF 5.1 is released.
Please take advantage of our UserVoice forums (https://windowsserver.uservoice.com/forums/301869-powershell) to tell the PowerShell team of issues you encounter in WMF 5.0, Windows 10 or Windows Server 2016 Technical Preview releases.
Your input matters and the information in UserVoice will be used to identify and prioritize the most critical items to address in Windows Server 2016 and WMF 5.1.
From Windows PowerShell product group blog