As far as XFree86 version 4.1, you can see http://people.debian.org/~cpbotha/xf410_potato/ Penguin wrote:
Given that I am super paranoid, maybe my old Debian 2.2r2 Potato is the best bet for me. Is there any reason why I may not be able to upgrade X to XFree 4.1 with this version of Potato?Thanks :)