How Does an Application Server Deliver a Cache Command
Set expireTime to a value greater than 0 when calling the Creating Device Commands API.
expireTime indicates the command expiration time, which is measured in units of seconds. Specifically, the validity period of the command is expireTime seconds. The command will not be delivered after the specified time elapses. If this parameter is not specified, the default validity period is 48 hours (86400 seconds x 2).