Usage API requires a DateStamp to indicate the date of the change. This date is in universal time (UTC).

How to get the current date & time in UTC ? Here is a solution in a few programming languages.

PHP

gmdate(DATE_ISO8601)

C#

DateTime.UtcNow.ToString("u")

Java

java.time.Instant.toString()

Ruby on rails

Time.now.utc.iso8601

Javascript

new Date().toISOString()