[ubuntu-uk] Updating previous ISO with zsync

[Rob Beard]

Hi folks,

I've just checked the Virgin Media mirror and it appears it hasn't been 
updated for Ubuntu 9.10 (it still has the RC version at the moment).  I 
remember reading something possibly a few days ago about being able to 
update the old image to the new image using zsync so it only downloads 
the changes.

I just wondered if anyone knew how to do this?

Ta,

Rob