Powershell script to convert all .xls documents to .xlsx in a folder and delete the old one(full auto)

ConvertXLS.ps1

$xlFixedFormat = [Microsoft.Office.Interop.Excel.XlFileFormat]::xlOpenXMLWorkbook
write-host $xlFixedFormat
$excel = New-Object -ComObject excel.application
$excel.visible = $false
$folderpath = "D:\Users\Username\Desktop\test"
$filetype ="*xls"
Get-ChildItem -Path $folderpath -Include $filetype -recurse | 
ForEach-Object `
{
	$path = ($_.fullname).substring(0, ($_.FullName).lastindexOf("."))
	
	"Converting $path"
	$workbook = $excel.workbooks.open($_.fullname)

	$path += ".xlsx"
	$workbook.saveas($path, $xlFixedFormat)
	$workbook.close()
	
	remove-item $_.fullname
	
}
$excel.Quit()
$excel = $null
[gc]::collect()
[gc]::WaitForPendingFinalizers()