"Invalid" means that a copy used to exist in the cache, but it is no longer current.
Thus they often preserve features and expressions which are no longer current in the spoken language.
A married woman could not historically act as next friend, but this practice is no longer current, at least in the United States.
I'll tell the tower your pilot status is no longer current.
It's just that their opinion of her was influenced by social customs no longer current.
And it alerts you of things you've got on your computer that are no longer current.
Many Muslims feel that the novel reflects badly on their culture, as the information covered is no longer current.
For one, the address is no longer current, and two others did not reply to requests to permit use of their names.
Only new records can be inserted, and existing ones updated by setting their transaction end time to show that they are no longer current.
Twenty-five years after most medical students graduate, the hard subjects they concentrated on are no longer current.