When PowerShell 3.0 is installed, I can force PowerShell to start using the version 2.0
-Version
Starts the specified version of Windows PowerShell.
Ente
You can run 2.0 runtime command by creating new PSSession.
Register-PSSessionConfiguration -Name PS2 -PSVersion 2.0 –ShowSecurityDescriptorUI
# Please consult system admin when your run set-item and Enable-WSManCredSSP command
Set-Item wsman:localhost\client\trustedhosts -value * -Confirm:$false -Force
Enable-WSManCredSSP -Role Client –DelegateComputer * -Force
Enable-WSManCredSSP -Role Server -Force
# For test purpose
# Get-WSManCredSSP
# get-item wsman:localhost\client\trustedhosts
$cred = Get-Credential
$session = New-PSSession -ComputerName $env:COMPUTERNAME -authentication credssp -ConfigurationName PS2 -Credential $cred
Enter-PSSession $session
# 2.0 runtime
Add-PSSnapin microsoft.sharepoint.powershell
$web = Get-SPWeb http://SPSite/
$web.Url
Exit-PSSession
Unregister-PSSessionConfiguration -Name PS2
Disable-WSManCredSSP -Role Client
Disable-WSManCredSSP -Role Server
If you don't exit PSSession, you can run 2.0 runtime command from Powershell ISE 3.