7.2 update instructions

[Yasha Karant]

I have burned the current production SL 7.2 4 Gbyte install DVD. The DVD 
boots but does not seem to have an upgrade option, only an install 
option.  Note that I plan to overwrite all files/partitions used by the 
system (but not /home , /opt , /usr/local that is a separate partition 
from /usr, and the like).

Currently, a number of add-on repositories (e.g., elrepo) for 7.1 are 
searched by the software installer.  Will these be saved and used for 
7.2 or must these manually either be saved or reinstalled after the 7.2 
update?

Are there instructions (URL?) for the upgrade, or is there a mechanism 
to invoke the DVD-based installer to do the update?  I do not want to 
use an Internet update because of the latency -- I want to do the 
upgrade from local (DVD) media.  Is this possible?

Yasha Karant