The order sender may cancel the order before it is executed.
Unexecuted orders are automatically canceled after 30 days from the date of opening.
An order expiration date is a date when the order is automatically canceled if it is not executed by this date.
The date is specified in milliseconds which have passed since the beginning of the Unix epoch until the expiration date.
The expiration time varies from 1 minute to 30 days.
The time is specified in milliseconds that have passed since the beginning of the Unix epoch.
See the Order binary format page.