Upgrading Ubuntu server

I'm not quite sure why I'd not got round to upgrading my Ubuntu server locally, but... I hadn't.

Took me a wee while to work out exactly how to do it, so I thought I'd post the results of my searches here... so that I have it for next time.

sudo -s
apt-get update
apt-get upgrade
apt-get dist-upgrade

apt-get install upgrade-manager-core
do-release upgrade

Simple...