Update 2018
Starting with version 2018.1 Adaxes supports the latest version of Windows PowerShell installed on the same computer where Adaxes service runs including PowerShell 3.0 and later.
Original
Hello,
No, this is currently impossible. Adaxes supports .NET Framework version 3.5 and loads and uses this framework version, which includes PowerShell version 2 only. You can install a newer version of .NET Framework with new PowerShell features on the computer where Adaxes is installed, but you will not be able to use it with Adaxes.