I will need a script that will check the current system date against a date in a mySQL database entry, comparing if it has elapsed past the database date or not. This date is the 'expiration date'.
If the system time is earlier than the 'creation date' of the database entry, then request that the user adjust their system date before continuing.
If the system time has elapsed the 'expiration date' then deny access to the application.
There will be existing code to add this on to. Message me and i'll send it to you for reference.