Personal Ancestral File (PAF) will be discontinued by FamilySearch as of July 15th. They also will discontinue support of the genealogy software. It was popular many years ago partly because it was very chap at a time when genealogy software would cost over $100. PAf was first issued in 1984. Version 2 added GEDCOM support to move data between PAF and other genealogy programs. The last (and current) version, 5.2 was issued in 2002.The full report is at this FamilySearch blog post.
FamilySearch has realized that PAF is not as useful as it once was. More modern genealogy programs have much more capabilities. FamilySearch is recommending three alternatives: Ancestral Quest, Legacy Family Tree and RootsMagic. Persoanally, I think RootsMagic is the best of the three and it is what I have used for many years.