Upgrade Debian Sarge to Etch ?

[raphael]

To upgrade to etch:
modify your /etc/apt/sources.list and modify all those 'sarge' to 'etch'
and:
apt-get update && apt-get dist-upgrade

Besides that, I recommend you to first make a backup of your server. Also, the backups engine won't work after the upgrade, because of a change in tar's options.
I'm not aware of any other problem caused by the upgrade.