Debian GNU/Linux 5.0 (Lenny) becomes stable version on Valentine Day. We upgraded old stable 4.0 Etch server remotely and successfully.
Summary of upgrading procedures:
Update list of apt sources to Lenny release.
# vim /etc/apt/sources.list
Replace all 'etch' to 'lenny'.
Use aptitude to update local list of available packages
# aptitude update
# aptitude install apt dpkg aptitude
Use UUID insteads of old IDE device names to identify root filesystem for grub and filesystem table.
UUID of root filesystem can be found at /dev/disk/by-uuid directory.
# ls -l /dev/disk/by-uuid
Identify which root filesystem to be loaded at grub config.
# grep kopt /boot/grub/menu.lst
Editing grub configuration /etc/grub/menu.lst for UUID of rootfs.
From sth. like:
# kopt=root=/dev/hda3 ro
To sth. like:
# kopt=root=UUID=203d2285-2a7d-44a3-a254-552ed139e351 ro
and then run Debian's grub update program.
# update-grub
Next, editing filesystem table /etc/fstab for UUID of rootfs.
From sth. like:
/dev/hda3 / ext3 defaults,errors=remount-ro 0 1
To sth. like:
UUID=d0dfcc8a-417a-41e3-ad2e-9736317f2d8 / ext3 defaults,errors=remount-ro 0 1
Use aptitude to do full upgrade
# aptitude full-upgrade
Reboot your system after first full upgrade. And run aptitude again to upgrade other packages if any.