The last version of the XPG, the X/Open Portability Guide Issue 4 (also known as the Common Applications Environment Specification Issue 4 (CAE4)), was published in July 1992 by The Open Group.
Poslední verze XPG – X/Open Portability Guide Issue 4 (také známá jako Common Applications Environment Specification Issue 4 (CAE4)) byla vydána v červenci 1992 konsorciem The Open Group (původně X/Open).