It does not seem to exist!
i just had a horrible experience where i used the 1.7.2 installer to "upgrade" xampp. What it really did was overwrite xampp with a brand new site! good thing i made a backup of the directory or i would be very very SOL as there was no warning that it would erase my current configs or anything.
So it just seems that there is no upgrade installer for this version. There is 1.7.2 --> 1.7.3, there is 1.7.0 --> 1.7.1, but no 1.7.1 --> 1.7.2.. What gives?!?
http://sourceforge.net/projects/xampp/files/
any information appreciated thanks