downgrade vs upgrade

downgrade

verb
  • To revert software back to an older version. 

  • to reduce the official estimate of a storm's intensity. 

  • To reduce in complexity, or remove unnecessary parts; to dumb down. 

  • To place lower in position. 

  • To disparage. 

noun
  • A reduction of a rating, as a financial or credit rating. 

  • A downhill gradient on a road or railway. 

upgrade

verb
  • 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. 

  • To improve, usually applied to technology, generally by complete replacement of one or more components 

  • To replace with something better. 

  • To improve the equipment or furnishings of or services rendered to 

  • To improve in condition or status. 

adv
  • Up a slope or grade. 

noun
  • An upward grade or slope. 

  • An improvement 

  • An improved component or replacement item, usually applied to technology 

How often have the words downgrade and upgrade occurred in a corpus of books? (source: Google Ngram Viewer )