These are versions of the A and D series that use libc 4.4.4 instead
of libc 4.5.19, in case you don't want to upgrade the C libs yet. I'd
recommend you don't use these unless you "have" to. :^) 

I'm likely not going to be providing any more libc 4.4.4 compatible binaries
in the future, since I've upgraded my own machine to libc 4.5.19.

Pat