Can't change powershell version

I have a Windows 10 machine that is running Powershell version 5. When I type in $psversiontable, I get:

    PS C:\WINDOWS\system32> $psversiontable

 Name                           Value
----                           -----
PSVersion                      5.1.14393.1198
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.14393.1198
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

When I try to change version by typing in powershell -version 4.0, I still get this:

PS C:\WINDOWS\system32> $psversiontable

 Name                           Value
----                           -----
PSVersion                      5.1.14393.1198
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.14393.1198
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Do you know how I can run version 4?

Thanks!