A Powershell-Script that changes existing Teams/Unified Groups primary Mail address since Exchange Online Adress policies only apply to new groups

change-primary-address-existing-groups

Connect-ExchangeOnline

"DisplayName,Modified,Primary,Leftovers" | Out-File -FilePath modifications.txt

$UnifiedGroups = Get-UnifiedGroup -ResultSize unlimited

foreach ($Group in $UnifiedGroups) {
    $modified = $false

    foreach ($address in $Group.EmailAddresses){
        if ($address -match "@oldprimarydomain.tld"){
            # primaryAddress has not "SMTP:"
            $updatedAdress = $address -replace "@oldprimarydomain.tld","@groups.oldprimarydomain.tld"
            $primaryAddress = $updatedAdress -replace "SMTP:",""

            # Define new primary address, then remove old one
            $modified = $true
            Set-UnifiedGroup -Identity $Group.Name -PrimarySmtpAddress $primaryAddress
            Set-UnifiedGroup -Identity $Group.Name -EmailAddresses @{remove=$address}
         }
    }
    
    $updatedGroup = Get-UnifiedGroup -Identity $Group.Name
    $leftovers = $false
    foreach ($address in $updatedGroup.EmailAddresses){
        if ($address -match "@oldprimarydomain.tld"){
            $leftovers = $true
         }
    }

    $a = -join($updatedGroup.DisplayName,";",$modified,";",$updatedGroup.PrimarySmtpAddress,";",$leftovers)
    Write-Host $a
    $a | Out-File -Append -FilePath modifications.txt
}