DateTime to ISO8601
$offset = ([System.TimeZoneInfo]::Local).BaseUtcOffset.ToString() $offset = $offset.Substring(0,$offset.LastIndexOf(':')) $date.ToString("yyyy-MM-ddTHH:mm:ss.fff") + $offset
DateTime to ISO8601UTC
$date.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ss.fffZ")
Convert From Unix Time
[timezone]::CurrentTimeZone.ToLocalTime(([datetime]'1/1/1970').AddSeconds($UnixTime))
Convert To Unix Time
[int][double]::Parse((Get-Date ($date).touniversaltime() -UFormat %s))