Migrating Exchange Management Shell

Migrating the Exchange Management Shell (5.1 → 7.x)

The Exchange snap-in (Microsoft.Exchange.Management.PowerShell.SnapIn, .E2010, .Admin) is a binary snap-in that cannot load in PowerShell 7. This is the single most common — and hardest — blocker in Exchange-heavy repos. The fix is to stop loading a snap-in and instead connect to an Exchange endpoint, which works from any PowerShell edition.

On-premises Exchange → implicit remoting

# 5.1 (remove this)
Add-PSSnapin Microsoft.Exchange.Management.PowerShell.SnapIn

# 7.x — connect to the Exchange remoting endpoint instead
$session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri "http://<exchange-server>/PowerShell/" -Authentication Kerberos   # or Negotiate
Import-PSSession $session -DisableNameChecking -AllowClobber

# ... run Exchange cmdlets exactly as before ...

Remove-PSSession $session

The imported cmdlets keep the same names and parameters, so most script bodies are unchanged. Objects come back deserialized — properties survive, methods do not; rewrite any $mbx.SomeMethod() calls to use cmdlets.

Exchange Online → EXO REST module

For Exchange Online, do not use WinRM remoting; use the REST-based module (works natively on PS7):

Install-Module ExchangeOnlineManagement    # once
Connect-ExchangeOnline -UserPrincipalName admin@contoso.com
# ... Exchange Online cmdlets ...
Disconnect-ExchangeOnline -Confirm:$false

Prefer the -REST-backed cmdlets (Get-EXOMailbox, Get-EXORecipient, …) where available — they are faster and paginate better than the classic aliases.

Migration steps per script

1. Delete the Add-PSSnapin Microsoft.Exchange... line(s).
2. Insert the correct connect block (on-prem remoting vs EXO) near the top.
3. Add the matching disconnect/cleanup at the end (and in a finally).
4. Parameterize the endpoint/credentials — do not hardcode servers or secrets.
5. Replace method calls on returned objects with cmdlet equivalents.

Validation (Rung 4c — the honest limit)

Full behavioral parity needs a live Exchange/EXO environment, which this agent does not own. Do:

• Rung 1/2: parse + PSScriptAnalyzer clean (no snap-in remains).
• Prove the command surface matches after connecting:

  Get-Command Get-Mailbox | Select-Object -ExpandProperty Parameters
  

  Diff against the 5.1 parameter set.
• Use -WhatIf in a staging org for mutating cmdlets where supported.
• Otherwise record needs-live-env / manual-signoff. Do not claim runtime validation that requires infrastructure you cannot reach.