To improve, usually applied to technology, generally by complete replacement of one or more components
When you upgrade your standard of living, you become addicted to that standard of living.
To replace with something better.
I had to upgrade my anti-virus software to protect my computer from the newer threats.
To improve the equipment or furnishings of or services rendered to
They upgraded him to the latest model.
To improve in condition or status.
She upgraded to a more successful husband.
To replace a program with a later version of itself, a version having a higher version number or marketed under a more recent product name.
Having had an upgrade; having been improved or enhanced.