Well, in 8.0 they replaced the glibc with a newer version I believe, which is not backwards compatible. Not that bad though, since you can simply recompile most programs (configure, make, make install... has become quite easy).
Now, in 9.0 I heard that they switched to posix threads, which is bound to cause the same kind of compatibility issues, but who knows. I think they also put some pre-patches into the kernel, at least the keyboard fix for keybounce on Toshiba notebooks

But I think the Uplink bug with RedHat 8.0 was something about some library. Seems that this works better, now. Anyway, it installed cleanly without any problems, everything working, even tv-out, etc.