The 5th GM Reference was very similar to the 3rd Edition GM Reference, varying only in minor corrections, additions, and clarifications. The 5th Edition of the game included the revised GM Reference, a revised Player's Guide, and the Quasar RPG Referee Assistant for MS Windows (EXE). Otherwise, the 5th Edition utilized existing 3rd Edition products without modification.
The reference was released in RTF and DOC format; both are identical except in very minor formatting. The DOC version was released as a self-extracting archive (EXE).
Confusingly, the GM Reference itself contains "Fourth Edition" on the copyright page but uses the release date of the 5th Edition of the game (and does not reference the date of the 4th Edition) and is referred to by other materials (including the download page) as the 5th Edition.