Exchange 2016 Holiday Calendar Loading

As time goes by scripts get updated. Here is an updated version of my old () which was originally written for Exchange 2010 under Server 2008.

$inputfile = "C:\Input\<mycalendarfile.csv"
$Webservices = "C:\Program Files\Microsoft\Exchange\Web Services\2.2\Microsoft.Exchange.WebServices.dll"
$baseOU = "OU=Domain Users,DC=liquidobject,DC=com"
#Need to update each year, in the event we need to pull entries we can search of it potentially
$myyears = "2017-2018"
#If we need to run the once per year everyone run, set this to true
$YearlyRun = $false

#Testing mode options
$testmode = $false
$testuser = "mytestaccount"

####################### End Options ########################

if(!(Get-Module | where {$_.Name -eq "ActiveDirectory"})){Import-Module ActiveDirectory}
if(!(Get-PSSnapin -Name "Microsoft.Exchange.Management.PowerShell.E2010" -ErrorAction SilentlyContinue)){Add-pssnapin Microsoft.Exchange.Management.PowerShell.E2010}
if(!(Get-PSSnapin -Name "Microsoft.Exchange.Management.PowerShell.support" -ErrorAction SilentlyContinue)){Add-pssnapin Microsoft.Exchange.Management.PowerShell.support}

if(!(Test-Path $Webservices))
{
    Write-Host "`n`nExchange Web Services API is required and is not installed`nhttp://www.microsoft.com/en-us/download/details.aspx?id=28952`n"
    Exit
}
if(!(Test-Path $inputfile))
{
    Write-Host "`n`nInput file of: $inputfile is missing, cannot proceed without this file.`n`n"
    Exit
}
Write-Host "`nEWS Web Services - Loading"
Add-Type -Path $Webservices
Write-Host "EWS Web Services API - Loaded`n"

function New-CalendarItem {
    [CmdletBinding()]
    param(
        [Parameter(Position=1, Mandatory=$true)]$CalendarUser,
        [Parameter(Position=2, Mandatory=$true)]$Subject,
        [Parameter(Position=3, Mandatory=$true)]$Date
        )
    
    $sid = (Get-ADUser -Identity $CalendarUser).SID
    $user = [ADSI]"LDAP://<SID=$sid>"
    $service = New-Object Microsoft.Exchange.WebServices.Data.ExchangeService -ArgumentList ([Microsoft.Exchange.WebServices.Data.ExchangeVersion]::Exchange2010_SP1)
    $service.AutodiscoverUrl($user.Properties.mail)
    
    $Impersonate = (Get-Mailbox -Identity $calendaruser).PrimarySMTPAddress
    $ImpersonatedUserId = New-Object Microsoft.Exchange.WebServices.Data.ImpersonatedUserId -ArgumentList ([Microsoft.Exchange.WebServices.Data.ConnectingIdType]::SmtpAddress),$Impersonate
    $service.ImpersonatedUserId = $ImpersonatedUserId
    
    $appointment = New-Object Microsoft.Exchange.WebServices.Data.Appointment -ArgumentList $service
    $appointment.Subject = $Subject
    $startdate = Get-Date($Date)
    $appointment.Start = $startdate
    $enddate = (Get-Date($Date)).adddays(1)
    $appointment.End = $enddate
    $appointment.body = "Calendar Automation " + $myyears
    $appointment.LegacyFreeBusyStatus = "Free"
    $appointment.IsAllDayEvent = $true
    $appointment.IsReminderSet = $False
    $appointment.Save([Microsoft.Exchange.WebServices.Data.SendInvitationsMode]::SendToNone)
    $appointment = $null
    sleep 0.2
}

$mydata = Import-Csv $inputfile
Write-Host "Preparing to process" $mydata.count "calendar entries`n"

if($YearlyRun)
{
    $myusers = Get-ADuser -Filter {(mail -like "*") -and (ObjectClass -eq "user") -and (Enabled -eq $true)} -SearchBase $baseOU -Properties created | Select-Object samaccountname, created
}
else
{
    $mydays = (Get-Date).Adddays(-7)
    $myusers = Get-ADuser -Filter {(mail -like "*") -and (ObjectClass -eq "user") -and (Created -gt $mydays) -and (Enabled -eq $true)} -SearchBase $baseOU -Properties created | Select-Object samaccountname, created
}

$myusers = $myusers | Sort-Object samaccountname
if($testmode)
{
    $myusers = @{"samAccountName"=$testuser}
}

$today = Get-Date
$mycount = $myusers.count
$currentpos = 1
foreach($i in $myusers)
{
    Write-Host "Loading $currentpos of $mycount for:" $i.samaccountname
    foreach($entry in $mydata)
    {
        if($today -lt $entry.date)
        {
            #Write-Host $entry.date " - " $entry.Subject
            New-CalendarItem -CalendarUser $i.samaccountname -Subject $entry.Subject -date $entry.date
            sleep 0.2
        }
        else
        {
            if($YearlyRun) #only load past dates on the yearly run
            {
                New-CalendarItem -CalendarUser $i.samaccountname -Subject $entry.Subject -date $entry.date
                sleep 0.2
            }
        }
        sleep 0.1
    }
    $currentpos++
    sleep 1.2
}