More Upgrade

[ableasby at hgmp.mrc.ac.uk]

You are more safe if you start from scratch. Usually you'd
get away with not doing so. However, problems can arise
if we move applications or ACD files between releases. It
would also happen if we deleted an application (or combined
functionality of two programs into one).

All of these have happened. At best you may have old executables
lying around. At worst it might confuse (e.g.) GUI programs
into thinking non-existent programs are still there if, for
instance, an unused ACD file isn't deleted.

HTH

Alan