backport vs upgrade

backport

verb
  • To retroactively supply (a fix or a new feature) to a previous version of a software product at the same time or after supplying it to the current version. 

  • To re-release software on its original or a previous platform with new features, after its release on a different platform. 

  • To retroactively supply to (a previous version of a software product) a fix, or a new feature, at the same time or after supplying it to the current version. 

noun
  • An act of backporting. 

  • A software program that has been backported. 

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. 

noun
  • An upward grade or slope. 

  • An improvement 

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

adv
  • Up a slope or grade. 

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