Active directory migration with powershell - powershell

Question

I need to migrate from AD Windows2003Forest to AD 2016. I have below script to create users in bulk. My requirement is to map the same SID of older AD to new AD. For example in older AD SID='xyz' then it should be the same in newAD too as SID='xyz'
I am having all the users data along with SID in CSV format & am using below PowerShell script which is somehow not working. As of advice or suggestions.
powershell code snippent:
#Enter a path to your import CSV file
$ADUsers = Import-csv C:\scripts\newusers.csv
foreach ($User in $ADUsers)
{
$Username = $User.username
$Password = $User.password
$Firstname = $User.firstname
$Lastname = $User.lastname
$Department = $User.department
$OU = $User.ou
$sid = $User.sid
$UserPrincipalName = $User.UserPrincipalName
$DistinguishedName = $User.DistinguishedName
#Check if the user account already exists in AD
if (Get-ADUser -F {SamAccountName -eq $Username})
{
#If user does exist, output a warning message
Write-Warning "A user account $Username has already exist in Active Directory."
}
else
{
#If a user does not exist then create a new user account
#Account will be created in the OU listed in the $OU variable in the CSV file; don’t forget to change the domain name in the"-UserPrincipalName" variable
New-ADUser `
-SamAccountName $Username `
-UserPrincipalName $UserPrincipalName `
-Name "$Firstname $Lastname" `
-GivenName $Firstname `
-Surname $Lastname `
-Enabled $True `
-ChangePasswordAtLogon $True `
-DisplayName "$Lastname, $Firstname" `
-Department $Department `
-DistinguishedName $DistinguishedName `
-SID $sid `
-Path $OU `
-AccountPassword (convertto-securestring $Password -AsPlainText -Force)
}
}

Answer 1

You won't be able to assign a SID as that's generated by the domain controller based on a RID. If trying to migrate to a new forest then you'll need to perform a proper AD migration. The old SIDs will be copied onto the migrated users' SID history attributes to allow permissions based on the old SID to still work.
If you simply want to upgrade to a newer version of AD then you're better off joining a newer domain controller to your existing Active Directory forest / domain. The forest functional level mush be 2003 or higher.
As a side note, I'd recommend then getting rid of the 2003 servers as soon as possible as these are no longer supported by Microsoft.