Active Directory: Bulk Update User UPNs

#Bulk Update UPNs

Import-Module ActiveDirectory

#SPECIFY NEW SUFFIX AND OU TO CHANGE
$newSuffix = '@domain.com'
$ou = "OU=Users,DC=mydomain,DC=local"

#EXECUTE CHANGES
Get-ADUser -Filter * -SearchBase $ou | ForEach-Object {
$newUpn = $_.SamAccountName + $newSuffix
Set-ADUser -ID $_ -UserPrincipalName $newUpn
}