Restore-AdAttributes.ps1

<#
.Synopsis
   Restore select Ad Attributes from a mounted AD DS database
.DESCRIPTION
   This cmdlet will take a OU path as input, takes a backup of the attributes of all users
   in said OU, import the attributes from a currently mounted AD DS database into a
   hashtable, loop through each user in the OU and apply said attributes. Finally, a export
   of the users current attributes is saved in the same path as the backup for before/after
   comparisons
.EXAMPLE
   Restore-AdAttributes -OldAd contosodc01:777 -NewAd contosodc01 -$AdOuPath "OU=Users,DC=contoso,DC=co" -BkpPath "C:\Temp\Backup\"
#>
function Restore-AdAttributes
{
    [CmdletBinding()]
    [Alias()]
    [OutputType([int])]
    Param
    (
        [Parameter(Mandatory=$true,
                   ValueFromPipelineByPropertyName=$false,
                   Position=0)]
        [string]$OldAd,

        [Parameter(Mandatory=$true,
                   ValueFromPipelineByPropertyName=$false,
                   Position=1)]
        [string]$NewAd,

        [Parameter(Mandatory=$true,
                   ValueFromPipelineByPropertyName=$false,
                   Position=2)]
        [string]$AdOuPath,
        [Parameter(Mandatory=$true,
                   ValueFromPipelineByPropertyName=$false,
                   Position=3)]
        [string]$BkpPath
    )

    Begin
    {
        # Build list of Users
        Get-ADUser -Filter * -SearchBase $AdOuPath -Server $NewAd | Select samaccountname | Export-Csv -Path $BkpPath\Users.csv -NoTypeInformation
        $UserList = Import-Csv -Path $BkpPath\Users.csv
    }
    Process
    {
        foreach ($User in $UserList)
        {
            #Backup First
            Get-ADUser -Identity $User.SamAccountName -Properties * -Server $NewAd | Out-File "$BkpPath\$($User.SamAccountName)_before.txt"

            #Get Old Values
            $OldProps = Get-ADUser -Identity $User.SamAccountName -Properties * -Server $OldAd

            #Build Hash Tables
            [hashtable]$OldValues = [ordered]@{
                extensionAttribute1 = $OldProps.extensionAttribute1
                extensionAttribute2 = $OldProps.extensionAttribute2
                extensionAttribute3 = $OldProps.extensionAttribute3
                extensionAttribute4 = $OldProps.extensionAttribute4
                extensionAttribute5 = $OldProps.extensionAttribute5
                extensionAttribute6 = $OldProps.extensionAttribute6
                extensionAttribute9 = $OldProps.extensionAttribute9
                extensionAttribute13 = $OldProps.extensionAttribute13
                extensionAttribute14 = $OldProps.extensionAttribute14
                publicDelegates = [array]$OldProps.publicDelegates
                publicDelegatesBL = [array]$OldProps.publicDelegatesBL
            }

            #Set Old Values
    
            foreach ($O in $OldValues.GetEnumerator())
            {
                Set-ADUser -Identity $User.samaccountname -Add @{$($O.Key)=$($O.Value)} -Server $NewAd -Verbose 
            }

            #Export New Values
            Get-ADUser -Identity $User.SamAccountName -Properties * -Server $NewAd | Out-File "$BkpPath\$($User.SamAccountName)_after.txt"
    
            #Reset Hash Tables
            $OldValues.Clear()
        }
    }
}

Restore-AdAttributes