PowerShell script to bulk export PST from a CSV file

Hello,

I got the task to do a bulk export to PST file of 1000 users in my org from a CSV file.

I got the following PowerShell script working just fine:

$Users = Import-Csv c:\users.csv
 
foreach ($User in $Users)
{
 
Write-Host "`nStarted processing $User.FirstName" -ForegroundColor Cyan

$filename = $User.Alias

New-MailboxExportRequest -DomainController colodc2   -Mailbox $User.Alias -FilePath "\\colo\PST\$filename.pst"
}

My follow up question is:

Now I got the task to export only emails that are prior to July 18th 2011  (old emails) for each mailbox.

What should I add in my PowerShell script to accomplish the task?