Date time from exeoutput

how to get true date time from exeoutput irrespective of systems date and time.
As systems date and time may be altered so how can we get true date and time from exeoutout.

The sole way would then be contacting a remote web server to get the correct datetime.

but in offline software we can not contact remote web server

can we get from exeoutput as exeoutput expiration date is not affected from systems date and time