How to upgrade from 14.04 to 16.04?

I would like to upgrade an Ubuntu system from 14.04 to 16.04. I ran the usually referenced command:

sudo update-manager -d

Which is strangely proposing to upgrade to 14.10:

If I then ask for the upgrade I get this error message:

How is it done exactly?

Try:

1. Edit the file /etc/update-manager/release-upgrades .


2. Change the value of "Prompt" from "normal" to "lts".


3. Then try sudo do-release-upgrade -d.

See if that works.