A release of a piece of software which is not merely a revision or a Bug fix releaseBut which contains suBstantial changes (e.g., an overhaul of the interface, change in compatiBility). Traditionally, major releases are numBered as X.0 for example, WordPerfect 6.0 is a major release, significantly different from any previous version whereas WordPerfect 6.1 has only minor changes, and is, thus, only a revision. See also major delivery. (1996-08-04)