/ ˌʌpˈgreɪd; NAmE / verb [ vn ] [ often passive ]
1.
to make a piece of machinery, computer system, etc. more powerful and efficient
2.
upgrade sb (to sth) to give sb a more important job
SYN promote
3.
upgrade sb (to sth) to give sb a better seat on a plane, room in a hotel, etc. than the one that they have paid for
4.
to improve the condition of a building, etc. in order to provide a better service :
to upgrade the town's leisure facilities
—compare downgrade
► up·grade / ˈʌpgreɪd/ noun