Installs PowerShell/WMF 5.1 for applicable versions of Windows running on PowerShell 2.0 to 4.0. Includes script for getting PowerShell version for NinjaRMM.

Get-PowerShellVersion.ps1

#Requires -Version 2.0

<#
.SYNOPSIS
    Returns the version of PowerShell installed and updates a custom field in NinjaRMM
.DESCRIPTION
    Returns the version of PowerShell installed and updates a custom field in NinjaRMM if the Ninja Agent is installed.
.PARAMETER CustomField
    Sets what custom field to update.
    Defaults to "PowerShell" if not used.
.EXAMPLE
    -CustomField PowerShellVersion
#>

[CmdletBinding()]
param(
    [string]
    $CustomField = "PowerShell"
)
begin {}
process {
    $Version = "$($PSVersionTable.PSVersion.Major).$($PSVersionTable.PSVersion.Minor)"
    if ($(Get-Command "Ninja-Property-Set" -ErrorAction SilentlyContinue).Count) {
        Ninja-Property-Set "$CustomField" "$Version"
    }
    Write-Output "PowerShell: $Version"
}
end {}

Install-Powershell51.ps1

#Requires -Version 2.0

# Installs PowerShell/WMF 5.1 for applicable versions of Windows running on PowerShell 2.0 to 4.0

# Based on:
# https://github.com/MicrosoftDocs/PowerShell-Docs/blob/main/reference/docs-conceptual/windows-powershell/wmf/setup/install-configure.md

function Test-Win64() { return [IntPtr]::size -eq 8 }
function Test-Win32() { return [IntPtr]::size -eq 4 }
function Expand-ZIPFile($File, $Destination) {
    $shell = New-Object -ComObject shell.application
    $zip = $shell.NameSpace($File)
    foreach ($item in $zip.items()) {
        $shell.Namespace($Destination).copyhere($item)
    }
}

$OSVersion = [System.Environment]::OSVersion.Version
$Bitness = if (Test-Win64) { "64" }elseif (Test-Win32) { "32" }else { Write-Error "Unknown CPU Arch"; exit 1 }
if ($PSVersionTable -ge [Version]::new(5.1)) { Write-Host "Already running PowerShell 5.1"; exit 0 }
if ($OSVersion -ge [Version]::new(6, 4)) { Write-Host "Nothing to do."; exit 0 }

$TempFolder = $env:TEMP
$DotNetUrl = "https://go.microsoft.com/fwlink/?LinkId=397708"
$DotNetFile = "NDP452-KB2901907-x86-x64-AllOS-ENU.exe"

$ProductName = (Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion").ProductName
$DotNetRelease = (Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full' -Name Release).Release
$IsDesktop = if ($ProductName -like "*Server*") { $false }else { $true }
$IsServer = if ($ProductName -like "*Server*") { $true }else { $false }

# List of download options
$Downloads = @(
    [PSCustomObject]@{
        Url             = "https://go.microsoft.com/fwlink/?linkid=839523"
        Bit             = "64"
        File            = "Win7AndW2K8R2-KB3191566-x64.zip"
        DesktopMajor    = 6
        DesktopMinor    = 1
        DesktopMinBuild = 7601
        IsDesktop       = $true
        IsServer        = $true
    }
    [PSCustomObject]@{
        Url             = "https://go.microsoft.com/fwlink/?linkid=839522"
        Bit             = "32"
        File            = "Win7-KB3191566-x86.zip"
        DesktopMajor    = 6
        DesktopMinor    = 1
        DesktopMinBuild = 7601
        IsDesktop       = $true
        IsServer        = $false
    }
    [PSCustomObject]@{
        Url             = "https://go.microsoft.com/fwlink/?linkid=839516"
        Bit             = "64"
        File            = "Win8.1AndW2K12R2-KB3191564-x64.msu"
        DesktopMajor    = 6
        DesktopMinor    = 3
        DesktopMinBuild = 7601
        IsDesktop       = $true
        IsServer        = $true
    }
    [PSCustomObject]@{
        Url             = "https://go.microsoft.com/fwlink/?linkid=839521"
        Bit             = "32"
        File            = "Win8.1-KB3191564-x86.msu"
        DesktopMajor    = 6
        DesktopMinor    = 3
        DesktopMinBuild = 7601
        IsDesktop       = $true
        IsServer        = $false
    }
    [PSCustomObject]@{
        Url             = "https://go.microsoft.com/fwlink/?linkid=839513"
        Bit             = "64"
        File            = "W2K12-KB3191565-x64.msu"
        DesktopMajor    = 6
        DesktopMinor    = 2
        DesktopMinBuild = 9200
        IsDesktop       = $true
        IsServer        = $false
    }
    [PSCustomObject]@{
        Url             = "https://go.microsoft.com/fwlink/?linkid=839516"
        Bit             = "64"
        File            = "Win8.1AndW2K12R2-KB3191564-x64.msu"
        DesktopMajor    = 6
        DesktopMinor    = 3
        DesktopMinBuild = 9600
        IsDesktop       = $true
        IsServer        = $true
    }
)

# Install 4.5.2 if current version is older
if ($DotNetRelease -lt 379893) {
    Write-Host "Downloading .Net 4.5.2"
    $wc = New-Object System.Net.WebClient
    $output = "$TempFolder\$DotNetFile"
    $wc.DownloadFile($DotNetUrl, $output)
    Write-Host "Installing .Net 4.5.2"
    & $output /q /norestart
}

# Select the correct installer for our OS
$SelectedInstall = $Downloads | Where-Object {
    $_.Bit -like $Bitness -and
    $_.DesktopMajor -ge $OSVersion.Major -and
    $_.DesktopMinor -ge $OSVersion.Minor -and
    $_.DesktopMinBuild -ge $OSVersion.Build -and
    (if ($IsDesktop) { $_.IsDesktop -eq $IsDesktop }elseif($IsServer) { $_.IsServer -eq $IsServer })
} | Select-Object -First 1

# Change directory to $TempFolder
Push-Location -Path $TempFolder

Write-Host "Downloading WMF 5.1"

$wc = New-Object System.Net.WebClient
$wc.DownloadFile($SelectedInstall.Url, "$TempFolder\$($SelectedInstall.File)")

if ($SelectedInstall.File -like "*zip*") {
    Write-Host "Expanding Zip to $TempFolder"
    Expand-ZIPFile -File "$TempFolder\$($SelectedInstall.File)" -Destination "$TempFolder\"
    Write-Host "Installing WMF 5.1"
    & $TempFolder\Install-WMF5.1.ps1 -AcceptEULA
}
else {
    Write-Host "Installing WMF 5.1"
    & "$TempFolder\$($SelectedInstall.File)" /quiet /norestart
}
if ($LASTEXITCODE -eq 0) {
    Write-Host "Installed WMF 5.1!"
}
else {
    Write-Host "Failed to install WMF 5.1!"
    Write-Host "Installer returned exit code of $LASTEXITCODE"
}
exit $LASTEXITCODE

# Go back to previous directory
Pop-Location