Terry : Debian

Debian GNU/Linux

Installed using Lenny (stable) and want to use unstable (sid)?

/etc/apt/sources.list

Replace lenny or stable with sid

Manually update

aptitude update && aptitude safe-upgrade

Check distribution info:

cat /etc/debian_version

squeeze/sid
root@debian:~# cat /etc/issue
Debian GNU/Linux squeeze/sid \n \l{
root@debian:~# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux unstable (sid)
Release: unstable
Codename: sid

Remove old kernel, Debian will remove the folder in /lib/modules but Ubuntu does not.