I've been upgrading Debian continually since around 2000 (don't remember exactly). It's even the same disk image, migrated to various disks (using mdadm), expan

I've been upgrading Debian continually since around 2000 (don't remember exactly). It's even the same disk image, migrated to various disks (using mdadm), expanded, converted to ext3 from ext2. But not without pain, I've almost always needed to manually intervene and fix configuration files. So you need root shell.