/changelogs /powershell/windows-powershell-5-1-to-powershell-7

Windows PowerShell 5.1 to PowerShell 7: what changes and what breaks

updated 2026-10-21

tool: PowerShell
versions: Windows PowerShell 5.1 → PowerShell 7.x

PowerShell 7 (pwsh.exe) is the cross-platform successor of Windows PowerShell 5.1 (powershell.exe). It runs on modern .NET instead of .NET Framework, installs side by side with 5.1 (which stays part of Windows and is not updated with new features), and has its own profile, module folder and settings. Most scripts run unchanged; what breaks is mostly encoding defaults, removed Windows-only cmdlets (WMI, workflows, EventLog) and modules that depend on .NET Framework.

Check which one you are in

powershell

$PSVersionTable.PSVersion
$PSVersionTable.PSEdition      # Desktop = Windows PowerShell 5.1, Core = PowerShell 6/7

Differences that affect scripts

Area	Windows PowerShell 5.1	PowerShell 7
Executable	powershell.exe	pwsh.exe
Runtime	.NET Framework 4.x	.NET (Core)
Default file encoding	varies by cmdlet (ANSI, UTF-16LE, ASCII)	UTF-8 without BOM everywhere
WMI	Get-WmiObject and Get-CimInstance	Get-CimInstance only
Event logs	Get-EventLog and Get-WinEvent	Get-WinEvent only
Invoke-WebRequest	IE-based HTML parsing unless -UseBasicParsing	basic parsing only
Export-Csv	#TYPE line unless -NoTypeInformation	no #TYPE line
Profile folder	Documents\WindowsPowerShell	Documents\PowerShell
User module folder	Documents\WindowsPowerShell\Modules	Documents\PowerShell\Modules
Platforms	Windows only	Windows, Linux, macOS

New language features in 7

powershell

$name = $env:USERNAME ?? 'unknown'               # null-coalescing (7.0)
$config ??= @{}                                    # null-coalescing assignment (7.0)
$len = ${text}?.Length                             # null-conditional member access (7.1)
$mode = $IsWindows ? 'win' : 'other'               # ternary operator (7.0)
dotnet build && dotnet test                        # pipeline chain operators (7.0)
1..10 | ForEach-Object -Parallel { $_ * 2 } -ThrottleLimit 4   # parallel (7.0)

None of these parse in Windows PowerShell 5.1, so a script that uses them fails there with a parser error. Add #Requires -Version 7 at the top of such scripts to get a clear message instead.

Modules

Most Microsoft modules (Az, Microsoft.Graph, ExchangeOnlineManagement, MicrosoftTeams) support PowerShell 7.
PowerShell 7 also searches the Windows PowerShell module folders. Modules that cannot load in .NET can be loaded through the compatibility layer: Import-Module Name -UseWindowsPowerShell runs them in a hidden Windows PowerShell process and proxies the commands (returned objects are deserialized copies).
Some modules are still Windows PowerShell only. Check the module's documentation before moving a script.

Migrating a script

Run it under pwsh and fix errors from removed cmdlets (Get-WmiObject to Get-CimInstance, Get-EventLog to Get-WinEvent).
Check files it writes: if another program expects UTF-16 or a BOM, pass -Encoding explicitly.
Remove dependence on ParsedHtml from Invoke-WebRequest.
Update scheduled tasks and shortcuts from powershell.exe to pwsh.exe (with -NoProfile).

Sources

compare · powershellInvoke-WebRequest vs Invoke-RestMethod: which one to use in PowerShellInvoke-RestMethod parses JSON or XML into objects, made for APIs. Invoke-WebRequest returns the raw response with its status code, headers and content.flags · powershellExport-Csv -NoTypeInformation: remove the #TYPE line from CSV filesWindows PowerShell 5.1 writes a #TYPE header as the first line of Export-Csv output unless you pass -NoTypeInformation. PowerShell 6+ omits it by default.config · powershell$env:PSModulePath: where PowerShell looks for modules and how to add a folderPSModulePath lists the folders PowerShell searches to import and auto-load modules. Prepend a folder for the session, or in your profile for every session.cheat sheets · powershellPowerShell cheat sheet: files, objects, filtering, strings and error handlingPowerShell cheat sheet: find commands and help, work with files, filter and sort objects, format strings, hashtables, loops, errors and bash equivalents.