Scott Ehrlich wrote:

I was just curious what the fundamental differences were between the 4.x and 5.x branches?

quite extensive. just a few major components...

c4 c5 kernel 2.6.9 2.6.18 glibc 2.3.4 2.5 gcc 3.4.6 4.1.2 apache 2.0.52 2.2.3 php 4.3.9 5.1.6 mysql 4.1.22 5.0.45 pgsql 7.4.19 8.0.11(?) python 2.3.4 2.4.3

etc etc etc