Definitions of upgrade:

• noun:   the act of improving something (especially machinery) by raising it to a higher grade (as by adding or replacing components)

  Example: "The power plant received a new upgrade"

• noun:   hardware that provides better performance than an earlier version did
• noun:   the property possessed by a slope or surface that rises
• noun:   a reservation that is upgraded

  Example: "I got an upgrade to first class when coach class was full"

• noun:   software that provides better performance than an earlier version did
• noun:   an upward slope or grade (as in a road)
• verb:   give better travel conditions to

  Example: "The airline upgraded me when I arrived late and Coach Class was full"

• verb:   get better travel conditions

  Example: "I upgraded to First Class when Coach Class was overbooked"

• verb:   rate higher; raise in value or esteem
• verb:   to improve, especially something that was old or outdated

  Example: "I've upgraded my computer so I can run better software"

• verb:   give a promotion to or assign to a higher position