I've long been puzzled by the official advice on upgrading Drupal

It basically says you should delete everything, unpack a new Drupal version, and replace your customisations.

I like to use version control to manage my site.

My current project uses the pressflow fork of Drupal, I downloaded the current and new versions of this, added them to my repository and then upgrading my working copy is as easy as

Debian Etch has been serving me well for a few years with wonderfully easy and infrequent maintenance.

However it's at the end of its life

http://www.debian.org/News/2010/20100121

So I've upgraded to Lenny following these instructions

http://www.debian.org/releases/lenny/i386/release-notes/ch-upgrading.en....

It was remarkably painless

One small problem with the mail system.