I’m trying to upgrade my ubuntu to the latest LTS, and have tried editing my sources.list to the digital ocean mirrors:

deb http://mirrors.digitalocean.com/ubuntu-old/ saucy main restricted universe multiverse
deb http://mirrors.digitalocean.com/ubuntu-old/ saucy-updates main restricted universe multiverse
deb http://mirrors.digitalocean.com/ubuntu-old/ saucy-security main restricted universe multiverse

However, do-release-upgrade still fails with a lot of errors (small snippet of many):

Err http://mirrors.digitalocean.com trusty/multiverse i386 Packages

Err http://mirrors.digitalocean.com trusty/universe i386 Packages

Err http://mirrors.digitalocean.com trusty/main Translation-en_US

Err http://mirrors.digitalocean.com trusty/main Translation-en

Err http://mirrors.digitalocean.com trusty/multiverse Translation-en_US

Then it finally fails saying

No candidate ver:  libaudit0
No candidate ver:  libcogl-pango0
No candidate ver:  libcogl9
No candidate ver:  libgjs0c
No candidate ver:  libgnome-desktop-3-4
No candidate ver:  libmutter0
No candidate ver:  libunity-core-6.0-5
No candidate ver:  unity-common

Updating repository information

No valid mirror found

While scanning your repository information no mirror entry for the
upgrade was found. This can happen if you run an internal mirror or
if the mirror information is out of date.

Do you want to rewrite your 'sources.list' file anyway? If you choose
'Yes' here it will update all 'saucy' to 'trusty' entries.
If you select 'No' the upgrade will cancel.

Continue [yN]

Any tips on how to proceed? I imagine I somehow have an issue with my sources.list?