Future versions of Windows 10 (such as the Fall Creator Edition) are scheduled to deprecate PowerShell version 2. If you wish to disable version 2 manually, use the following command within an elevated PowerShell session.
Disable-WindowsOptionalFeature -Online -FeatureName MicrosoftWindowsPowerShellV2
Additional details can be found at https://www.petri.com/microsoft-deprecate-powershell-2-0-windows-10-fall-creators-update and https://blogs.msdn.microsoft.com/powershell/2017/08/24/windows-powershell-2-0-deprecation/