To put this in some perspective, I used Debian's debootstrap to install Debian Woody (2002 vintage) on a Linux 5 (I think?) kernel. It all worked as expected. I suspect the XWindows protocol is fairly backward, and you could recompile everything with the gcc Woody shipped. I guess that says a thing or two about Debian maintaining backward compatibility with older package formats too.

It's not a stunt I try to pull with Windows.