WordNet (r) 3.0 (2006):

upgrade
    n 1: an upward slope or grade (as in a road); "the car couldn't
         make it up the rise" [syn: ascent, acclivity, rise,
         raise, climb, upgrade] [ant: declension,
         declination, decline, declivity, descent,
         downslope, fall]
    2: software that provides better performance than an earlier
       version did
    3: a reservation that is improved; "I got an upgrade to first
       class when coach class was full"
    4: the property possessed by a slope or surface that rises [syn:
       upgrade, rise, rising slope]
    5: hardware that provides better performance than an earlier
       version did
    6: the act of improving something (especially machinery) by
       raising it to a higher grade (as by adding or replacing
       components); "the power plant received a new upgrade"
    v 1: rate higher; raise in value or esteem [ant: downgrade]
    2: to improve what was old or outdated; "I've upgraded my
       computer so I can run better software"; "The company upgraded
       their personnel"
    3: give a promotion to or assign to a higher position; "John was
       kicked upstairs when a replacement was hired"; "Women tend
       not to advance in the major law firms"; "I got promoted after
       many years of hard work" [syn: promote, upgrade,
       advance, kick upstairs, raise, elevate] [ant:
       break, bump, demote, kick downstairs, relegate]
    4: get better travel conditions; "I upgraded to First Class when
       Coach Class was overbooked"
    5: give better travel conditions to; "The airline upgraded me
       when I arrived late and Coach Class was full"

Moby Thesaurus II by Grady Ward, 1.0:

145 Moby Thesaurus words for "upgrade":
   abruptness, acclinate, acclivitous, acclivity, acculturate,
   advance, aggrandize, ameliorate, amend, anabasis, anabatic,
   ascendant, ascending, ascension, ascensional, ascensive, ascent,
   aslant, aslantwise, aslope, at a slant, atilt, better, boost,
   breakthrough, bring forward, civilize, clamber, climb, climbing,
   downgrade, downhill, edify, educate, elevate, elevation, emend,
   enhance, enlighten, ennoble, enrich, escalade, exalt, fatten,
   favor, forward, foster, fountain, go straight, graduate, gush,
   gyring up, hike, improve, improve upon, in the ascendant, increase,
   jet, jump, kick upstairs, knight, lard, leap, leaping, levitation,
   lift, make an improvement, meliorate, mend, mount, mounting,
   nurture, off plumb, pass, precipitousness, prefer, promote, raise,
   rakingly, rampant, rearing, refine upon, reform, rise, rising,
   rising ground, rocketing up, saltation, saltatory, scandent,
   scansorial, shooting up, skyrocketing, slantingly, slantways,
   slantwise, slaunchways, slopeways, slopingly, soaring, socialize,
   spiraling, spout, spring, springing, spurt, steepness,
   straighten out, surge, takeoff, taking off, tipsily, transfigure,
   transform, up, uparching, upclimb, upcoming, updraft, upgang, upgo,
   upgoing, upgrowth, uphill, uphillward, upleap, uplift, upping,
   uprisal, uprise, uprising, uprush, upshoot, upslope, upsloping,
   upsurge, upsurgence, upsweep, upswing, upward, upwith, vault,
   verticalness, wax, zooming



The Free On-line Dictionary of Computing (30 December 2018):

upgrade

   1. A new or better version of some hardware or software.

   Often used in marketroid-speak to mean "bug fix".

   2. The act of developing or installing a new version.

   (1995-03-14)