How does a program developer not know what his program does? Both of the people giving answers in the refererred thread are Foxit people and have access to the developers. According to the posts here, Foxit supported 98 through 2.2, which I think was through the summer of this year, 2008, and had 98 testing facilities. Presumably 2.3 came out of the same shop that produced 2.2 and the programmers had to know what worked in 98 and what worked only in XP to make it work under 98. They have been doing that for years. So the whoever wrote 2.3 should have known what they were doing that was XP/Vista only. And if it was XP/Vista only, why would they be uncertain if it would work or not? If they were using XP/Vista only code, they should know that it wouldn't work. Indeed, if they were using XP/Vista only code, how could it work under 98? Something seems strange, or missing, here. Does anyone know of any other program where the developer has said he doesn't if it works under 98 or not?